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									Zoonotic Diseases
Training Package
Zoonotic diseases
Session Title

                                        Zoonotic diseases: Session #

At the end of this module the participant should be able to:
• Define terms (zoonosis, emerging disease….)
• Classify zoonoses based on host, pathogen, transmission
• Understand the importance of zoonoses to One Health
• Discuss emerging and re-emerging zoonoses
• Understand reasons for disease emergence and re-
• Describe selected zoonoses important in their region
• Understand the principles of zoonosis prevention and

                                                          Slide 02
This presentation gives an overview of the importance of zoonotic
       diseases to human and animal health, their ecology and
     epidemiology, and measures used for their prevention and
    control. Examples used can be varied by trainers according to
              the relevance of zoonoses in their regions
Further information on zoonotic diseases, e.g. statistical data, can
                be found in the following websites:

                                                      3insert your company logo
                                      Zoonotic diseases: Session #


Zoonoses are infections which are naturally transmitted
 between vertebrate animals and people

Derived from the Greek ZOON (animals) and NOSES

People, animals, birds, arthropods and the inanimate
 environment are all involved in cycles of zoonotic

                                                        Slide 04
                                       Zoonotic diseases: Session #

Anthropozoonoses: Zoonoses where the main reservoir
of infection is non-human vertebrate animals
Most zoonoses are of this type e.g. bovine tuberculosis,
rabies, leptospirosis
Zooanthroponoses: Diseases that mainly affect people,
which may be transmitted to animals, which then act as
temporary reservoirs of infection
Examples are Mycobacterium tuberculosis in dogs,
infectious hepatitis in apes, H1N1 pandemic influenza
in pigs

                                                         Slide 15
                                        Zoonotic diseases: Session #


Vector: an organism, often an invertebrate arthropod,
that transmits a pathogen from reservoir to host, e.g.
mosquito and JEV
Reservoir: a long-term host of a pathogen, e.g. mouse
and hantavirus (in this instance the host can also be the
vector as the virus is transmitted via mouse excreta)
Fomite: an inanimate object that can transmit an
infectious agent, e.g. medical equipment and Ebola

                                                          Slide 05
                                           Zoonotic diseases: Session #


           Environment                  Host

 Zoonotic diseases are multifactorial and their occurrence is
affected by interactions between the host, the agent and the

                                                             Slide 14
                                     Zoonotic diseases: Session #


Approximately 1500 infectious diseases are recognized
                     in humans
           Of these 60% are due to zoonoses
   75% of recently emerging infectious diseases (EID)
       have been caused by zoonotic pathogens

                                                       Slide 05
                                    Zoonotic diseases: Session #


            WHO/FAO/OIE definition
 “An emerging zoonosis is a zoonosis that is newly
recognised or newly evolved, or that has occurred
 previously but shows an increase in incidence or
 expansion in geographical, host or vector range”

                                                      Slide 06
                                       Zoonotic diseases: Session #

           DISEASES CAN BE…

 A known agent appearing in a new geographic area
   A known agent or its close relative occurring in a
          hitherto unsusceptible species
A previously unknown agent detected for the first time

  Wild animal reservoirs represent a more frequent
               source of ‘new’ agents

                                                         Slide 07
                                       Zoonotic diseases: Session #


1. Factors explaining emergence are complex, e.g.
   genetic drift and shift (influenza) and modification
   of the immunological status of populations (change
   in susceptibility of populations; vaccination)
2. Social and ecological conditions influencing
   population growth and movement, food habits and
   the environment may be more important
3. Influence of changing environment on reservoirs,
   vectors and victim species
4. Population expansion and urbanisation

                                                         Slide 08
                                     Zoonotic diseases: Session #


5. Increasing contact between human populations, wild
   and domestic animals expose people to zoonotic
   agents by direct or indirect contact
6. Growing population of drug and alcohol impaired and
   immuno-suppressed people worldwide are at higher
   risk of zoonoses
7. Many of the common, life threatening infections
   associated with HIV are zoonoses

                                                       Slide 09
                                       Zoonotic diseases: Session #


Some diseases associated with changing farming
practices, trade and consumer habits (Salmonella
Enteritidis, E. coli O:157)
Live animal trade introduced screwworm to Libya,
Ebola-like virus in monkeys in quarantine in the USA
and monkeypox to the USA
Epidemics of BSE due to many factors including use of
ruminant protein as feed
Adaptation of avian influenza strain H5N1 to people is a
current cause of concern

                                                         Slide 17
                                    Zoonotic diseases: Session #


Poverty affected communities
People with low population immunity (HIV, age)
Areas of altered climate and increased vector range
Areas of political unrest and population migration
Natural disaster affected areas
Areas of deforestation and altered biodiversity
People affected by global trade and travel

                                                      Slide 10

• Human health (death and disability)
• Animal health (death and disability)
• Economic losses due to livestock culling, deaths and
  decreased production
• Cost of control programs
• Trade implications
• Indirect effects on people due to psychological
  trauma (loss of pets, culling, loss of valuable animals)
  and impact on cultural traditions, etc.
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                               Zoonotic diseases: Session #


     Type of infectious agent
 (bacteria, fungus, virus, parasite)

      Mode of transmission

      Type of reservoir host

                                                 Slide 11
                                      Zoonotic diseases: Session #


Transmission of infections may be direct, indirect via
   arthropod vectors, or from environmental foci

      Direct zoonosis
      Saprozoonosis                     www.who.int

          (e.g. direct & metazoonosis)

                                                        Slide 12
                                         Zoonotic diseases: Session #


  Direct and                               Metazoonosis
                   Cyclozoonosis       (e.g. Rift valley fever, JE)
   Leptospira in    Taenia solium                    eggs
   animal urine

Contaminated            Pigs
   water                            Livestock     Mosquitoes
    in humans                               Humans

                                                           Slide 13

Diseases of vertebrate animals which can affect
people, the infectious agents of which are either
  capable of replicating in inanimate sites, or
   require an inanimate environment for the
 development of an infectious stage of their life
     eg. histoplasmosis, Toxocara canis, certain
              food-borne diseases
                                       Zoonotic diseases: Session #


 Most zoonoses have more than one reservoir species
and can be transmitted to people from many different
animal species e.g. salmonellosis, rabies, leptospirosis,
                      Nipah virus
Zoonoses can be referred to by their association with a
 particular species e.g. zoonoses of cattle, zoonoses of

                                                         Slide 14
                         Zoonotic diseases: Session #




                                           Slide 18
                                      Zoonotic diseases: Session #


    Bacillus anthracis, Gram-positive sporing rod
   Worldwide, Russia, Asia, Africa, South America
‘Hot spots’ in warm humid areas where natural cycles
   All mammals susceptible but pigs, dogs and cats
                relatively resistant
Birds can disseminate spores, chickens resistant, some
                  birds susceptible

                                                        Slide 19
                                        Zoonotic diseases: Session #


Organisms enter via -
       Skin (cutaneous anthrax)
       Lungs (pulmonary anthrax, woolsorter’s disease)
       Gastrointestinal tract
Clinical signs include -
       Eschar in humans (black necrotic skin lesion)
       Sudden death in ungulates, blood from the nose
       and other body orifices; septicemia in humans

                                                          Slide 20
                                         Zoonotic diseases: Session #



                                                           Slide 21
                                      Zoonotic diseases: Session #

Animal by-products, wool, hides, bone meal, meat,
imported curios etc. involved in spore transmission
Cutaneous infections most common, inhalation,
intestinal, person-to-person rare
1-7d incubation, spores germinate, papules, vesicles,
edema, fatal septicemia
Agricultural workers, vets, rural communities,
travellers etc.
Bioterrorism agent – US postal workers affected

                                                        Slide 22
                                        Zoonotic diseases: Session #


B. melitensis - goats, sheep (cattle, camels, dogs,
people). Asia, Africa, Mediterranean and South America
B. abortus – bovines, (dogs, people). Worldwide
B. suis – pigs (people). South America, Southeast Asia,
United States, Australia
B. canis - domestic and wild carnivores (people). Many
countries worldwide

Primary hosts susceptible, disease in other hosts varies in
                                                          Slide 23
                                                    Zoonotic diseases: Session #


                                  Vegetative endocarditis in a person,
Brucellosis transmitted in milk          caused by brucellosis
     and causing orchitis                      Ufuk Yetkin 2007
           WHO and FAO

                                                                      Slide 24
                                         Zoonotic diseases: Session #

Chronic, long term infections, rarely fatal
Ingestion, venereal
Concentration of animals during calving, during milking,
commoner in dairy cattle
Organism persists in cool temperatures
Abortion depends on stage of gestation
Carnivores, birds aid in spread of fomites
Flu-like symptoms in humans, including muscle and
joint pains, fever, cough, (rarely endocarditis)

                                                           Slide 25
              Case study for discussion of Brucellosis in India

Small Ruminant Research, Volume 14, Issue 2, Pages 161-165 (August 1994),
Occurrence of abortions and seroprevalence of brucellosis in goats and sheep,
S.V. Singha, N. Singha, M.P. Singhb, H. Shankara, D.D. Lalwanib

Occurrence of abortions, still births and seroprevalence of brucellosis were
studied in native, unvaccinated and organised flocks of goats (Barbari,
Jamunapari, Sirohi, Kutchi, Jakharana, and Marwari) and sheep (Muzaffaragri)
with abortion problems during the period from 1985 to 1990. In 6 years, 8.4%
lambs and 13.4% kids were lost due to abortions and still births. Incidence of
abortions were recorded as 12.3% and 6.8% and still births 1.0% and 1.6% in
goats and sheep, respectively. Serologically, 0.6% goats and 3.6% sheep were
found to be positive for brucellosis by standard tube agglutination test (SAT).
The regular screening of the flocks for Brucellosis and elimination of positive
cases partially helped to lower the incidence of Brucellosis in these flocks.

                                     Zoonotic diseases: Session #


Yersinia pestis, Gram-negative rod
Rodent disease transmitted by fleas (carried by 30-
40 species of rodent, 1500 types of fleas)
Complex sylvatic (wild) cycle
Rodents act as reservoir and amplifying host
Humans accidental hosts
Carnivores infected by ingestion

                                                       Slide 26
                                         Zoonotic diseases: Session #


Capture of rats in Indochina to
       prevent plague
      www.asnom.org/ en/423_peste.html

                                                           Slide 27
                                     Zoonotic diseases: Session #


Disease of poor living conditions, rats and fleas
Spread by fleas, handling plague material
Human-human transmission (pneumonic
Buboes (cutaneous lymphadenitis),
septicemia, pneumonia

                                   Buboes in groin

                                                       Slide 28
     Bubonic plague in Mongolia, October 4, 2004, a case study for
There have been several cases of Bubonic Plague (also know as Black Plague, Black Death, Pestilence)
in Mongolia recently, resulting in two deaths so far this year. According to D. Tserennorov, vice
director for the Center for Infectious Diseases with Natural Foci, two people in the Darbi Soum of
Gobi-Altai Aimag were infected. One of the victims died on September 18th and 62 others who have
had, or may have had direct contact with the man are now quarantined.

On September 19, 2004, a woman from Ilbenkh in the Bayankhongor Aimag was infected after
skinning a marmot. Seventy people who have had, or may have had direct contact with her have not
shown any symptoms of the disease so far.

The Mongolian government has declared a state of emergency in these, and surrounding areas. The
State Disaster Protection Agency warns people not to hunt or eat marmots.

The Plague is transmitted via several methods. They include:
Bites from rodent fleas
Exposure to humans with the pneumonic form of the plague
Handling infected carcasses
Scratches or bites from infected domestic cats
Exposure to aerosols (small air-borne particles breathed in from infected animals and humans)

                                      Zoonotic diseases: Session #


Disease described in dogs in 1850
Weil’s disease described in people in 1880
Organism first isolated in Japan in 1914 - now 7
pathogenic species & over 200 serovars recognised
By 1940 leptospirosis established as a major animal
and public health problem
Occupational disease
Associated with natural disasters e.g. floods

                                                        Slide 29
                                             Zoonotic diseases: Session #


Direct anthropozoonosis (or via fomites)
Host-adapted serovars in maintenance
hosts which act as reservoirs,
inapparent infections in these animals
Herbivores long shedding, carnivores short
Severe infections in secondary hosts (non-reservoir)
All serovars capable of infecting any animal. Dominant serovars
vary between regions, e.g. serovar Autumnalis in Thailand
Moist environmental conditions favor survival outside hosts,
endemic zones worldwide

                                                               Slide 30
                                       Zoonotic diseases: Session #

Occupational hazard: in rice-growing communities, e.g.
July 2008 578 infections, 15 dead in Thailand. Cattle,
pigs and rodents possible reservoirs, via urine
contaminating paddy fields.
Recreational risks: Sabah, Malaysia, 2000 Eco-challenge
race – 50 out of 80 athletes contracted leptospirosis
Natural disasters: Typhoon Ketsana, Manila, Philippines
in 2009, approx 170 deaths, hundreds infected, 1
million doses of prophylactic doxycycline, hospitals
coped poorly

                                                         Slide 31
                                      Zoonotic diseases: Session #

Contact with infected urine or contaminated
water, seasonal spring/summer in cooler climates
Entry via intact mucous membranes, aerosols or
skin abrasions, occupational disease
Anicteric (without jaundice) disease is common form in
Australia, vague symptoms, flu-like, fever, headache,
Icteric disease very severe, more common in Asia,
rodent hosts of serovars
Person-person transmission rare, dead-end hosts

                                                        Slide 32
    THAILAND (case study to discuss)

                               Am. J. Trop. Med. Hyg., 76(1), 2007, pp. 135–8
Kamphaeng Phe Province (gray    (www.ajtmh.org/cgi/reprint/76/1/135.pdf)
                            Zoonotic diseases: Session #



             NIPAH VIRUS

                                              Slide 33
                                        Zoonotic diseases: Session #

          Family Rhabdoviridae, Genus Lyssavirus

1. Classical rabies
2. Lagos bat virus
3. Mokola virus
4. Duvenhage virus
5. European bat virus 1
6. European bat virus 2
7. Pteropus Lyssavirus (Australian bat lyssavirus)

                                                          Slide 34
                                       Zoonotic diseases: Session #

                 CLASSICAL RABIES
Virulent rabies spread from Europe to Asia and other
regions by infected dogs; many countries worldwide
Dogs most important domestic hosts, cats, cattle and
other domestic animals commonly involved
Many wild reservoirs which differ between regions;
principally canids (foxes, wolves, jackals) but also
mongooses, skunks, raccoons, bats
Some countries free by eradication e.g. UK
Direct zoonosis – bites, mucosal exposure, other routes
e.g. corneal transplants

                                                         Slide 36
                                          Zoonotic diseases: Session #


infection of neurons
spread to
neurons in ganglia or                     Dumb
spinal cord, spread to
brain                    clinical signs
                                             2-3 days
  to salivary glands,
  skin                                    Virus shedding

                                                            Slide 37
                                     Zoonotic diseases: Session #


Transmission to people mainly by bites via virus in
saliva, aerosol transmission extremely rare
Aerosol transmission, found in bat saliva in zoos
Incubation 4 days – 6 years, depends on bite site
Clinical rabies invariably fatal
Prodromal period (behavioural changes)
Excitative period (hydrophobia, aerophobia in people);
a dog in India bit 40 people/9 dogs in 4 hours
Paralytic period (dumb rabies)

                                                       Slide 38
                                       Zoonotic diseases: Session #


Haematophagous (blood sucking),
insectivorous and frugivorous (fruit eating) bats all
can transmit rabies and related viruses
Spread by bites and scratches from infected animals
Neurological signs in bats and humans similar to
classic rabies
Cases reported in Australia, Europe and USA
Vampire bats are reservoirs of classical rabies, South

                                                         Slide 35
                               Zoonotic diseases: Session #


   Pteropus spp. fruit bats are known
    reservoirs of a number of other
 zoonotic viruses worldwide, including
  Nipah virus, Hendra virus, Ebola and

                                                 Slide 47

The genus Henipavirus is a newly described genus
including 2 newly emerged viral agents, Nipah virus
  and Hendra virus, first identified in Malaysia and
               Australia respectively

                                                 Slide 50
                                        Zoonotic diseases: Session #

                     HENDRA VIRUS

Named for a suburb in Brisbane, infected 23 horses and
3 people in Queensland in 1994
Survey identified infected fruit bats; postulated that bat
to horse contact had occurred due to habitat changes
Occupational hazard, with infections in veterinarians
and horse-associated workers
Disease has killed four of the seven people infected
since its discovery

                                                          Slide 51
                                        Zoonotic diseases: Session #

                   NIPAH VIRUS
Malaysia and Singapore 1998/9
Mild disease in pigs
Encephalitis & respiratory infections in people, cats and
dogs in contact with pigs
Malaysia 257 human cases/105 deaths; Singapore 11/1
1.1m pigs slaughtered
Pteropus spp. bats implicated, closely
related to Hendra virus
Seasonal, may be linked to bats
                                           www.abc.net.au, AFP: Raul Arboleda

                                                                    Slide 52
                                       Zoonotic diseases: Session #

                  NIPAH VIRUS
Eight outbreaks in Bangladesh and India since 1998
have been associated with bats contaminating fresh
date palm juice, collected overnight to make palm
sugar (255 cases/136 deaths)

Bats have been seen to drink from the containers used
to collect the raw juice, contamination

Humans commonly drink the raw juice in the
villages associated with the industry

Fruit bats are ‘anthropophilic’ in India and
Bangladesh (live in close proximity to humans)

                                                         Slide 53
        Case study of Nipah outbreak in Bangladesh
The Daily Star, Wednesday, January 20, 2010
Nipah virus claims 3 in Faridpur
Three members of a family under Bhanga upazila of the district died within a week after they contracted
encephalitis caused by Nipah virus.
Faridpur Civil Surgeon Dr Bashirul Islam stating the report of Institute of Epidemiology, Disease Control and
Research and National Influenza Centre, Bangladesh (IEDCR) yesterday confirmed the death of the three from
Nipah virus that spread from the swab of bats.
The dead were identified as Karuna Biswas, 30, of Algi village under Bhanga upazila, her daughter Dipti Biswas, 11,
and nephew Sanu Biswas, 10. All the three drank raw date juice before they contracted the disease, the family
sources added.
On information, a special team of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDRB)
led by Faridpur Civil Surgeon Dr Bashirul Islam visited the village on Saturday and collected the sample of blood of
the three. After examining the blood sample the IEDCR authorities identified the disease as encephalitis, says Dr
Bashirul, adding that the disease originated from raw date juice contaminated by the swab of bats.
All people of the district were advised to collect date juice covering the mouth of jars with nets so that bats cannot
sink their tongues into the jar, he said.
While talking to The Daily Star, Director of the IEDCR Prof Mahmudur Rahman said this is the first incidence of
death due to Nipah virus this year. Last year encephalitis broke out in Rajbari and Manikganj. But very few people
died because of the government's early detection programme. Under the programme a regular surveillance has
been in place in Faridpur, Rajbari and Madaripur since 2006.
The major outbreak took place in Faridpur in 2004 causing death to at least 17 people of Laxmipur village under
Sadar upazila.
                                      Zoonotic diseases: Session #

Outbreak in China in November 2002
SARS coronavirus
Flu-like symptoms
Case fatality rate in humans of almost 10%
Related to trade in wild animals, civet cats (which had
been in contact with bats in the farms), market hygiene
Humans infected via processing, cleaning
Human-to-human transmission, 8096 cases, 774 deaths
Disease control by quarantine, thermal imaging used to
detect cases early in disease at airports

                                                        Slide 54
         SARS outbreak – discuss origins, spread,
          ecological and economic implications
Severe Acute Respiratory Syndrome
CBC News Online | Updated April 22, 2004
Origin of the crisis:
Health officials declared in July 2003 that the global epidemic of severe acute respiratory
syndrome was over, but in December 2003 and January 2004, China confirmed four new cases of
SARS in southern Guangdong province. Those patients recovered, but on April 22, 2004, China
confirmed two more suspected cases of the disease, one in Beijing and one in Anhui, a province
in eastern China.
The first case of SARS appeared in November 2002. It killed 800 people around the world,
including 44 in Toronto. The disease killed 350 in China. That country later ordered the killing of
some 10,000 civet cats, suspected to be carriers of SARS. The weasel-like mammals are
considered a delicacy in Guangdong and are served in wild-game restaurants.
Two inquiries into the political and medical reaction to the SARS outbreak released reports in
April 2004. Both reports focused on the need to improve public health spending on infectious
disease prevention, identification, control and containment – and the importance of clear
communication and cooperation among all levels of government and health care providers.

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                                     Zoonotic diseases: Session #


Approximately 60 viruses, of which 29 are human
Yellow fever, Japanese encephalitis, Murray Valley
encephalitis, West Nile virus, Chikungunya virus
Important causes of viral encephalitides
All are zoonoses (although dengue and yellow fever
are now adapted to humans in
urban cycles)

                                                       Slide 39
                                        Zoonotic diseases: Session #


Distributed throughout Asia, world’s most important
 cause of epidemic encephalitis
Maintained in nature in a complex cycle involving many
 species of birds, mammals and insect vectors
Transmission cycles depend on human
 practices such as rice cultivation
 (for mosquito habitat) and livestock

                                                  Night heron

                                                                Slide 44
                                        Zoonotic diseases: Session #


Certain water birds, e.g. egrets, cormorants and herons
play a role as reservoirs
Pigs are the primary amplifying hosts of JEV; susceptible
pigs infected during seasonal epidemics coinciding with
rainy season
Pigs sustain viremia sufficient to infect mosquito
Cattle, chickens, humans are dead end hosts

                                                          Slide 43
                                                  Zoonotic diseases: Session #

Human disease: fever, nausea, vomiting, seizures, coma,
CNS signs; 20% case mortality; estimated 50,000
cases/year; 20% case disability rate; universal infection
by 15years old in rural areas
Control difficult due to extensive mosquito breeding
areas in rice fields
Immunisation of humans the only
option, possibly barriers/traps
round villages

          11 more succumb to Japanese
       Encephalitis in India, toll reaches 311.

                                                                    Slide 45
                                        Zoonotic diseases: Session #


28 species of mosquito can be infected with JEV but not
all are competent vectors, mainly the Culicoides group

Pigs and horses affected clinically, abortion in sows and
encephalitis in horses

Birds introduce virus into virus-free areas by migrating
while viremic

Piglets affected soon after start
of rains

                                                          Slide 46
Evolution of JE control in Thailand
    Case study for discussion

                                       Zoonotic diseases: Session #


First recognized in the Korean war in the 1950s along
 the Hantan river
New strain causing Hantavirus cardiopulmonary
 syndrome recognized in America in 1993
Rodent reservoir

                                    www.kuleuven.be/ rega/mvr/research.html

                                                                   Slide 55
                                         Zoonotic diseases: Session #


RNA viruses of the Bunyaviridae family
Spread by aerosolized rodent excreta or rodent bites
No human-to-human transmission
Endemic in China, SE Asia, America and Europe
Renal and (cardio)pulmonary syndromes
Control by controlling rodent populations, do not stir
 up dust when cleaning rodent-infected areas

                                                           Slide 55
                                        Zoonotic diseases: Session #

                INFLUENZA VIRUSES

Highly contagious acute respiratory disease, high
mortality, low mortality
Type A viruses are the only zoonotic ones, H5N1 and
H1N1 are 2 newly emerged virus strains of global concern
Humans, pigs, horses and avians are commonly affected,
other animals rarely (cattle, mink, seals)
Poultry and pigs are the main source
of infection for humans, occupational

                                                          Slide 56

Disease in humans self-limiting, uncomplicated
respiratory illness with fever; severe disease and
deaths have occurred
Pigs also affected, initially via contact with infected
humans or infected fomites, then via direct contact
with secretions and feces
May 2nd 2009 virus isolated from pigs in Alberta,
Canada; to the end of 2009 14 countries had reported
the pandemic strain in pigs to the OIE

                                                      Slide 60
Chickens appear refractory to infection, however
commercial turkeys have shown some signs, mostly
decrease in egg production in breeding flocks; older
turkeys more susceptible to infection; turkey infections
reported from Canada, USA and Chile
Turkeys are unique in that, like pigs, they have receptors
for both avian and mammalian influenza A receptors in
their tissues; they are commonly infected with strains
from wild birds and pigs; role of turkeys in the
epidemiology of pandemic H1N1 unclear

                                                     Slide 62
April 21st 2009 – novel strain identified in Mexico and the USA,
first called ‘Swine Flu’, now named Pandemic (H1N1) 2009 virus
This ‘triple reassortant strain’ contains a unique combination of
gene segments donated by viruses originating from 3 species
(humans, pigs, birds) and 2 hemispheres
Each segment has been nested in well-established swine
influenza lineages for over 10 years; ancestors circulated
undetected for over 10y before emerging in humans
The strain has developed strong ‘mammalian-like’ hemagglutinin
(HA) receptor specificity, and can no longer replicate in aquatic
waterfowl, their historic natural reservoir

                                                           Slide 58
June 11th 2009 – WHO raised the influenza alert level to Level 6
– pandemic!
2009-2010: Pandemic (H1N1) 2009 Influenza spread to many
countries worldwide; virus disseminated worldwide in just a
few weeks
Feb 2010: >213 countries reported lab confirmed cases, at least
16,500 deaths, the majority in Europe and the Americas –
underrepresentation as many deaths are never tested or
recognised as influenza related. Activity in Africa reported but
low, circulation continuing in South and SE Asia
Seasonal Influenza B viruses now predominant in S. Asia; Global
Influenza Surveillance Network monitors global circulation of
viruses including pandemic, seasonal and others

                                                            Slide 59
Clinical signs in pigs mild: fever, slight cough,
sneezing, nasal discharge
Clinical signs in humans usually mild: fever, slight
cough, sneezing and nasal discharge; vomiting and
diarrhea in up to 38% of cases
H1N1 infections in pigs similar in duration to other
influenza viruses
Sampling by nasal swab: virus shed for up to 20d
post-clinical signs; pig herds rapidly clear the virus

                                                     Slide 61
Global concern is that H1N1 viruses might acquire
virulence markers by reassorting with viruses such
as H5N1 that cause severe disease in humans

Such reassortments are more
likely to occur in ‘mixing vessels’
(pigs, turkeys) than in humans;
risk highest in pigs

                                                 Slide 63
Pigs infected with pandemic (H1N1) 2009 virus should be
managed similarly to herds infected with any other swine
influenza virus; control outbreaks with bio-safety measures,
avoiding dissemination to humans and animals
Thus, restrictions of trade or slaughter of pigs as a public health
intervention are irrational actions (statement from Canadian
scientists – alluding to the slaughter of all pigs in the country by
Egyptian authorities, with subsequent loss of livelihood for
small, poor communities)
Countries should implement vigilant surveillance for, and
monitor for changes in the structure and behavior of, the virus

                                                                Slide 64
                                      Zoonotic diseases: Session #


Avian influenza less host-specific than mammalian
strains, many avian species infected; both low
pathogenic (LPAI) and highly pathogenic (HPAI) strains
are recognised in poultry
HPAI A/H5N1 was isolated from chickens and humans
in Hong Kong in 1997, causing 6 human deaths.
Following this a larger outbreak occurred in Hong Kong
in 1999
Aggressive virus eradication was used in HK, with
millions of chickens being culled, also in-contact dogs
and cats

                                                        Slide 65
• Further outbreaks in SE Asia in 2003/4/5 may have
  been spread via migratory ducks, probably
  originating from China, and then locally via live bird
• Other HPAI strains have occasionally caused human
  infections (H7 and H9 strains)

                                                      Slide 66
 H5N1 IN 2010 – discuss importance of H5N1

Peak in poultry in 2006 – 63 countries infected in
Europe, Asia and Africa
April 2010: 493 human cases/292 deaths (in 15
countries); 260m poultry culled; estimated $20bn
economic damage worldwide; devastated
livelihoods at the family farm level.
Now endemic in poultry in 5 countries: Egypt,
Indonesia, Vietnam, China and Bangladesh; sporadic
outbreaks in: Bhutan, Cambodia, Laos, India,
Myanmar, Nepal

                                               Slide 67
    COUNTRY (APRIL 2010)
          Iraq         3/2
          Turkey       12/4
          Azerbaijan   8/5
          Cambodia     10/8
          Thailand     25/17
          China        38/25
          Egypt        109/34
          Vietnam      119/59
          Indonesia    163/135
          Other        6/4
  500th human case reached in July 2010

                                          Slide 68
Endemic factors: tens of millions of free-
ranging ducks; significant broiler production;
live bird markets; high human and animal

H5N1 sero-conversion has occurred rarely in
pigs, virus has not been isolated


                                                 Slide 69
Vaccination used in all those countries except Bangladesh; all
other countries have a slaughter policy (e.g. Thailand, Europe)
Other policies: improved poultry biosecurity, enhanced
surveillance capacities; prompt reporting to OIE World Animal
Health Information System (WAHIS)
UN proposed framework for sustaining momentum; three
streams of work for national, regional and global authorities
• prevention and control of HPAI
• adoption of One Health approaches
• readiness for response to influenza pandemics

                                                            Slide 70
                 ECHINOCOCCUS spp.
Dogs are the primary host of E. granulosus
Eggs are ingested by intermediate hosts including
people and sheep
Cysts transmitted from sheep to dogs by eating offal
Onchospheres penetrate intestine and travel to liver
and lungs; grow slowly into hydatid cysts; may reach
20cm in diameter; surgery required to remove cysts
Control programs aimed at treating dogs for
tapeworms and breaking transmission cycle
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                   Hydatid disease

Hydatid cyst in human liver

                                 Cyst in child’s
      Cyst removal
     Hydatid Disease Control in Nepal – case study
Butchering in Nepal is generally done by the people of lower caste, who are usually less
educated. It is common practice to slaughter animals in open air, mainly near water sources like
the bank of a river, streams, ponds and public taps where meat and viscera can be washed
conveniently. Sometimes, household yards and near by streets are used as slaughter and selling
site. The discarded offal and slaughter by products are then usually left as such in the slaughter
site or disposed near by. In the countryside, animals are usually slaughtered and sold during
periodic local markets, or during religious ceremonies. Once the animal is slaughtered, all the
meat is usually consumed immediately as there is no access of ordinary people to refrigeration.
The situation is somewhat different in the cities, but there is virtually no infrastructure to
accommodate the slaughter and sale of meat.

A large number of stray dogs occur in Nepal, mainly in the cities, besides owned dogs by
individuals or the community. The dogs survive on garbage and remain wandering in search of
food, mainly around the slaughter site. Butchers often throw inedible meat pieces, viscera or
bones to these dogs or the dogs have easy access to the slaughter wastes, which if contains cyst
of Echinococcus infects them. As the dogs are freely roaming, they defecate on wherever they
wish, commonly on the river bank or any other free space which is often used as playground or
foraging ground, and thus re-infect man and animals. This is assumed to be the most common
mode of transmission throughout Nepal.

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                                       Zoonotic diseases: Session #


Historically the task of veterinarians – now One Health
National and international eradication programmes e.g.
rabies, TB, brucellosis, HPAI
Slaughter inspection of food animals
Prophylactic vaccinations mainly in animals
Therapy of animals with zoonotic diseases
Vector and reservoir population control (arthropods,
Surveillance for diseases of importance in the region
e.g. Japanese encephalitis, rabies, HPAI
                                                         Slide 71
                                      Zoonotic diseases: Session #


           Breaking cycles of transmission
   Enhancement of host resistance e.g. vaccination,
           Destruction of infectious agents
  Prevention of environmental degradation to reduce
disruption of natural balances among hosts, agents and
                   the environment
  Integration of medicine and veterinary medicine in
                 approaches to control
                     One Health

                                                        Slide 72
                                       Zoonotic diseases: Session #


Sensible personal hygiene
• Wash hands after handling animals
• Wash hands before eating or drinking
• Disinfect and dress wounds as soon as possible
• Wash eyes if urine splashed
• Wear gloves and a face mask if unsure
Working with sick wildlife
• Take special precautions e.g. Personal protective
  equipment (PPE)
                                                         Slide 73
                           Zoonotic diseases: Session #


         Avian Influenza

                                             Slide 74
                                           Zoonotic diseases: Session #


Surveillance, quarantine, movement control
Serological testing - card test, Rose Bengal test, milk
ring test, slaughter positives
Segregation at parturition, sanitation
Vaccination - S19 (live), 45/20 (killed)
No vaccines for pigs or dogs

                                                             Slide 75
                                        Zoonotic diseases: Session #

               CONTROL OF PLAGUE

Rodent control (cover feed, alter habitats)
Flea control in rodents and pets
Effective diagnosis, early warning, treatment and
Avoid handling or eating meat from sick animals

                                                          Slide 76
                                          Zoonotic diseases: Session #


Vaccination of cattle, pigs, deer, dogs
Need virulent, local serovars in vaccines, little cross-
immunity, killed vaccines, annual re-vaccination
Protective clothing, e.g. boots, eye protection, gloves in
Avoid contact with animal urine
Control of wild reservoirs e.g. Rodents
Differential diagnosis - brucellosis, meningitis, hepatitis,

                                                            Slide 77
                                               Zoonotic diseases: Session #

                   CONTROL OF RABIES
Strict quarantine laws for imported dogs plus pre-entry vaccination
Other laws in endemic areas - limit dog ownership, destruction of
unregistered dogs
Pre-exposure (humans), cell culture vaccine, 1ml on day 0, 7 and 21
Animal vaccines use attenuated live virus or recombinant orthopox
virus incorporating the virus glycoprotein gene
Oral administration in wild animals (foxes, raccoons) via bait
stations has been highly successful in Europe and the USA
Human post-exposure vaccination very effective, can also use
hyper-immune serum if unvaccinated

                                                                 Slide 78
        Discuss methods of control for rabies in Bali
 Poisoned darts are being used to kill stray dogs in Bali
The beautiful resort and formerly rabies-free Indonesian island of Bali is under siege
from the deadly virus.
The outbreak that was initially publicized in late 2008 continues to this day with the
human death toll up to 78, and probably many other deaths are going unreported.
The problem has got to the point where rabies vaccine supplies on the island are
running low and may soon not be available.
The Australian-based Bali Street Dog Fund has vaccinated thousands of dogs to help
curb the outbreak and the Bali government has even used controversial methods like
picking out strays for killing.
Since the beginning of the outbreak, 200,000 dogs have been killed, though many find
this an ineffective method to control rabies.
Rabies is an acute viral infection that is transmitted to humans or other mammals
usually through the saliva from a bite of an infected animal. It is also rarely contracted
through breaks in the skin or contact with mucous membranes.
The only treatment for human exposure to rabies is rabies-specific immune globulin
and rabies immunization. Appropriate treatment started soon after the exposure will
protect an exposed person from the disease.
                 Rabies – case study for discussion

Indian man eats dog’s heart to “prevent rabies”
A stray street dog that had terrorized an Indian village last week biting at least seven
    people found its most bizarre fate.
His latest victim, a 30 year old laborer from a village on the outskirts of Ranchi decided
    to make sure he wouldn’t get rabies from the dog in the most unusual manner—
    eating the dog’s heart.
According to reports, the man went after the dog and killed it by throwing rocks at it.
    After the dog died, he removed the dog’s heart with a pair of scissors and ate it
The man after being questioned by local media about seeking medical care responded
    that he didn’t need medical help since he treated himself by eating the dog’s
Not only is rabies transmitted by animal bites but also by the butchering of rabies-
    infected or sickly animals where the virus could get into the persons eyes or
                                       Zoonotic diseases: Session #


Australian, African and European bat lyssaviruses
Similar to rabies
Spread by bites and scratches from infected animals
Prevention: avoid being bitten by bats, handle animals
with care and protective clothing. Wash wounds
thoroughly with soap and water
Vaccination with rabies vaccine

                                                         Slide 79
                                        Zoonotic diseases: Session #


Control by biosecurity, quarantine, closed flocks,
movement control, vaccination, live bird market
improvements, hygiene, cancelling shows etc.
Eradication of virulent viruses by slaughter programs
Control of the disease in wild birds impractical, may
be a source of infection via migration for non-
endemic areas; flock biosecurity important
Human H5N1 vaccines currently being tested

                                                          Slide 80
                                        Zoonotic diseases: Session #


Zoonotic diseases pose global epidemic health risks
Increased risk of disease due to increased contact
between humans and animals, wild and domestic
Zoonotic diseases most likely to originate in SE Asia,
Africa and China
Air travel allows disease to spread rapidly around the
Future control of emerging infectious diseases will rely
on the adoption of One Health principles

                                                          Slide 82
                                        Zoonotic diseases: Session #

At the end of this module the participant should be able to:
• Define terms (zoonosis, emerging disease….)
• Classify zoonoses based on host, pathogen, transmission
• Understand the importance of zoonoses to One Health
• Discuss emerging and re-emerging zoonoses
• Understand reasons for disease emergence and re-
• Describe selected zoonoses important in their region
• Understand the principles of zoonosis prevention and

                                                          Slide 02
Zoonotic Diseases
 Training Package
   Thank you
Training resources
                                       Zoonotic diseases: Session #


Are the following statements true or false?

a) Zoonotic diseases are easy to control and eradicate
   from populations
b) Humans are often incidental hosts of zoonotic
c) Zoonoses are not important today because we have
   antibiotics and other drugs to control them
d) Zoonotic diseases can only be transmitted by wild
                                     Zoonotic diseases: Session #


1. Why have trade and travel played important roles in
   the spread of zoonoses?
2. Name and describe 3 recently emerged zoonoses
3. What is the difference between an emerging and a
   re-emerging disease?
4. List 5 reasons for disease emergence
                                    Zoonotic diseases: Session #


1. Draw the lifecycle of a direct, indirect, cyclo-
   and meta-zoonosis.
2. Name 3 arboviral infections in Asia and discuss
   the similarities and differences in their
   epidemiology. What information would you
   need to formulate a control program for each of
3. Following heavy flooding in Asia, name 3
   zoonoses that could occur and what could be
   done to control, prevent or prepare for them?
                                      Zoonotic diseases: Session #


Look at the newspaper clipping from the Bangkok Post
1st October 2009 and answer the following questions:

1. Explain why zoonotic disease outbreaks often occur
   after natural or man-made disasters.
2. What conditions are likely to exacerbate the disease
3. What would you need to do to minimize the risk of
   disease outbreaks related to emergency situations
   such as these?
Zoonotic diseases: Session #
                      Further case studies


See page 67 for Asian case studies on:
 Brucellosis

 H5N1 (“Avian Influenza”)

 Severe Acute Respiratory Syndrome (SARS)

 Nipah Virus

 Hydatid Disease/ Cystic Echinococcosis

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                                 Zoonotic diseases: Session #


Games can be developed and played to highlight
      important or relevant information
                 Card games
                 Quiz games
                Board games
               Memory games

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