CommDisBullSept04 - Communicable Diseases Surveillance Bulletin

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					                         Communicable Diseases

                           Surveillance Bulletin
                                           September 2004
A bimonthly publication of the National Institute for Communicable
                         Diseases (NICD)
                        of the National Health Laboratory Service (NHLS)

  Eastern Cape ostriches during an outbreak of avian influenza H5N2 in August 2004.


  Epidemic prone disease surveillance table.......................................................                       2

  Avian influenza in South Africa .........................................................................              3

  Malaria in South Africa .......................................................................................        4

  Typhoid Fever ......................................................................................................   6

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 author, the Bulletin and the NICD
         EPIDEMIC PRONE DISEASE SURVEILLANCE : JANUARY-AUGUST                                   CUMULATIVE      ECP     FSP     GAP     KZP    LPP     MPP     NCP     NWP      WCP   RSA

         AFP, cases from whom specimens                                                           2003          23      8       28      29     54      5       3       18       20    188
         have been received                       < = 15 years                                    2004          11      6       18      25     51      9       4       17       19    160

         Measles, IgM positive results            All ages                                         2003         0       0       7       U      1       3       1       0        U     13
                                                                                                   2004         0       0       307     U      2       6       4       0        2     325

         Rubella, IgM positive results from                                                       2003          23      24      72      U      27      35      9       36       U     226
         measles IgM negative patients            All ages                                        2004          63      2       78      U      8       56      3       48       8     266

         CCHF                                     All ages                                        2003          0       0       0       0      0       0       0       0        0     0
                                                                                                  2004          0       1       0       0      0       0       1       2        0     4

         Rabies, human                            All ages                                         2003         0       0       0       5      0       0       0       0        0     5
                                                                                                   2004         0       0       0       5      0       1       0       0        0     6

                                                  All ages                All serotypes            2003         3       10      84      11     0       4       0       3        35    150
                                                                                                   2004         5       6       88      13     1       3       0       3        30    149

                                                                          Serotype b               2003         0       3       11      0      0       1       0       1        5     21
                                                                                                   2004         0       2       10      0      0       0       0       0        3     15

         Haemophilus influenzae, invasive         Age < 5 years           Non-serotype b          2003          0       0       9       0      0       0       0       0        2     11
                                                                                                  2004          0       0       2       1      0       0       0       0        3     6

                                                                          Non-typable             2003          1       1       22      4      0       0       0       0        7     35
                                                                                                  2004          0       2       19      2      0       0       0       0        7     30

                                                                          Unknown serotype         2003         1       5       2       6      0       1       0       1        9     25

                                                                                                   2004         3       2       8       4      1       1       0       1        4     24

         Meningococcal disease                    All ages                                        2003          5       14      127     6      1       11      4       21       47    236
                                                                                                  2004          18      15      102     14     9       6       4       13       45    226

                                                  All ages                                        2003          44      63      1254    119    20      70      9       83       259   1921
                                                                                                  2004          97      130     1283    319    47      117     11      73       327   2404

                                                  Age < 5 years                                    2003         20      33      347     46     2       21      2       17       129   617
                                                                                                   2004         44      42      393     107    13      29      3       20       141   792
         Streptococcus pneumoniae, invasive
                                                  Penicillin, non-                                2003          7       9       246     26     1       10      1       5        61    366
                                                  susceptible, all ages                           2004          20      25      328     75     9       23      0       17       76    573

                                                  Susceptibility                                  2003          12      1       91      17     3       6       0       28       24    182
                                                  unknown, all ages                               2004          10      17      143     21     8       16      0       6        39    260

         Salmonella species - invasive isolates          All ages         All serotypes excl.      2003         4       14      183     0      0       4       1       1        31    238
                                                                          S. typhi                 2004         2       7       232     22     4       3       0       4        21    295

         Salmonella species - enteric isolates    All ages                All serotypes excl.      2003         38      11      25      0      0       3       0       1        66    144
                                                                          S typhi                  2004         36      17      93      22     14      2       0       17       58    259

         Salmonella typhi                         All ages                                        2003          1       0       6       0      3       0       1       0        0     11
                                                                                                  2004          5       0       12      5      3       7       0       0        5     37

         Shigella species                         All ages                All serotypes            2003         24      8       22      0      1       3       0       0        50    108
                                                                                                   2004         42      17      86      43     13      5       0       5        114   325

         Vibrio cholerae 01                       All ages                All serotypes            2003         53      0       3       0      0       66      0       1        1     124
                                                                                                   2004         26      0       3       0      0       217     0       46       0     292
    U = unavailable, 0 = no isolates received     Note: The above are NICD laboratory data and do not nececessarily reflect a quantitative measure of disease in the country.
                        Gillian de Jong & Lucille Blumberg, Epidemiology Unit, NICD

INTRODUCTION                                               there are no commercial poultry farms in the area
On the 6th of August, 2004 officials reported an           and testing of backyard poultry has shown no
outbreak of highly pathogenic avian influenza              evidence of infection to date. Strict movement
(HPAI) A subtype H5N2 in ostriches in the Blue             restrictions are enforced by road-block cordons
Crane Municipal District of the Eastern Cape.              and the public is prohibited from removing any
Initial reports reported over 1500 ostrich deaths          poultry (including ostriches, birds, and other fowl)
on 2 farms in Middleton near Somerset East.                or their products from the area.
Subsequently, several additional farms in the area
have serological evidence of infection.                    The original source of the infection is still
                                                           unknown. Surveillance of wild fowl in the area has
AVIAN INFLUENZA IN OSTRICHES                               proved negative thus far and epidemiological links
Avian influenza of low pathogenicity (LPAI) has            are still under investigation. The virus spreads
previously been isolated from ostriches in South           via direct contact with infected birds and indirectly
Africa. Several subtypes were identified during            through contaminated environmental sources.
the 1990’s including H7N1 (1991, 1992), H5N9               Exports of poultry and poultry products from
(1994) and H9N2 (1995). Avian influenza H5N2               South Africa have been voluntarily suspended.
occurred in Zimbabwe in 1995 but this subtype
had not previously been isolated in South Africa.          AVIAN INFLUENZA A AND HUMAN DISEASE
Generally avian influenza viruses in ostriches are         Human disease caused by avian influenza varies
considered to be of low virulence for chickens.            in presentation and ranges from conjunctivitis to
The first report of HPAI in ostriches came from            a flu-like illness, severe pneumonia, adult
Italy during a poultry outbreak in 1999.                   respiratory distress syndrome and even death.
                                                           Several subtypes of avian influenza have been
INFLUENZA A H5N2 IN THE EASTERN CAPE                       associated with clinical disease in humans. A large
In mid-July, farmers on 2 farms in Middleton               outbreak of human disease occurred in the
reported illness and significant deaths in their           Netherlands following influenza A H7N7 in poultry
ostriches which prompted an investigation. The             in 2003. Eighty-nine people were infected with
ostriches presented with features of sinusitis, sub-       one death. More recently, the outbreak of
mandibular swelling, green urine and                       influenza H5N1 in Thailand and Vietnam resulted
conjunctivitis. The virus was initially isolated at        in at least 34 officially confirmed cases with 23
Stellenbosch from tissue taken from an ostrich             deaths. Infections in this area are ongoing. Unlike
on the first affected farm. This was confirmed by          other subtypes of HPAI, influenza A H5N2 has not
RT-PCR at Onderstepoort Veterinary Institute as            been shown to cause infection in humans.
influenza A, ostrich H5N2 subtype. The cleavage            Previous outbreaks of this subtype in poultry in
site sequence was that of a highly pathogenic              Italy (1997) and Texas (2004) were not associated
virus having multiple basic amino acids at this            with human disease based on serological and
site. At least 1500 ostriches have died of the             clinical surveillance.
disease. Subsequently, at least 3 additional farms
have tested positive on serological surveillance.          An outbreak response team from the NICD has
                                                           recently visited the affected farms to conduct
The Department of Agriculture has responded                clinical and serological surveillance for human
definitively to the outbreak and has established           infection. Serological testing will be performed
a quarantine area and extensive serological                using a micro-neutralisation assay. Of concern
surveillance.                                              is the extensive exposure of individuals working
                                                           on the affected farms, initially with little personal
The quarantine includes an area with a radius of           protective equipment. Guidelines have also been
30 km around the 2 farms where the infection               issued by the NICD regarding the use of personal
was originally confirmed. In addition, culling of          protective gear in high risk personnel, the
ostriches and poultry in the affected area was             detection and management of clinical cases and
performed. Over 13 600 ostriches have been                 recommended diagnostic procedures for
culled thus far in an effort to eliminate the virus        suspected infection. Human influenza vaccine
and contain its spread. Farmers will be                    has been recommended for all exposed personnel
compensated for culled ostriches. Fortunately,             to prevent concurrent infection with both human

and avian influenza, which could result in genetic    tested but it is possible that they had also died of
re-assortment and the possible emergence of a         avian influenza. More recently, Malaysia reported
human-avian reassortant.                              infection in chickens and China revealed the
                                                      isolation of influenza A H5N1 in pigs.
SOUTH-EAST ASIA                                       CONCLUSION
From January to March 2004, Thailand and              The current outbreak in the Eastern Cape has
Vietnam had reported 34 officially confirmed          been devastating for all concerned. It is hoped
human H5N1 cases with 23 deaths to the World          that the response will be effective in preventing
Health Organisation (WHO). Vietnam announced          further spread of the infection. Ongoing
that it was free of avian influenza in March.         serological surveillance in the affected area and
However, in June lethal outbreaks among poultry       the rest of the country is essential for containment
of HPAI H5N1 were again reported to the World         of the virus. Controlling re-infection will be a
Organization for Animal Health by China,              challenge as ostriches are raised outdoors and
Indonesia, Thailand and Vietnam. This was             therefore have uncontrolled contact with the
followed by an official report on 12 August by the    environment including wild birds. Although human
Vietnamese Ministry of Health of 3 human deaths       infection has not been documented, surveillance
from confirmed avian influenza H5 infection.          of exposed personnel will continue and the use
These were the first reported human cases of          of appropriate personal protective equipment
H5 since March. The cases included a woman            must be encouraged. South Africa must continue
from Hau Giang and 2 children from Ha Tay in          to be vigilant both for the prevention of further
the North of Vietnam. The dead woman was one          economic losses in the industry and for the global
of 4 people from Hau Giang who died between           prevention of the emergence of a new human
29 July and 2 August. None of the others were         pandemic strain of influenza.

                          MALARIA IN SOUTH AFRICA
        Lucille Blumberg , Devanand Moonasar5, Jan van den Ende2, Karen Barnes2,3, Lee Baker3,4
            1.    National Institute for Communicable Diseases
            2.    National Malaria Advisory Group
            3.    Department of Pharmacology, University of Cape Town
            4.    Amayeza Information Centre
            5.    National Department of Health, Malaria Control Programme

Malaria is endemic in the low altitude areas (below   education and communication. Malaria control
1 000 metres above sea level) of the northern         policy is formulated at national level, whilst the
and eastern parts of South Africa along the border    implementation of policy takes place at provincial,
with Mozambique and Zimbabwe, with trans-             district and local levels. These policies are in
mission mainly in the Limpopo, Mpumalanga and         keeping with WHO guidelines.
KwaZulu-Natal (KZN) provinces. Occasionally
limited focal transmission occurs in the North-West   MALARIA TRENDS
and Northern Cape Provinces along the Molopo and      Subsequent to robust malaria interventions,
Orange Rivers, respectively. Annual transmission      notification of malaria cases and deaths declined
occurs mainly in the rainy summer months, from        from 62 200 cases and 480 deaths (case fatality
October to May, peaking from February to April.       rate 0.8%) in 1999/2000 to 11 025 cases and 75
The population at risk for contracting malaria is     deaths (case fatality rate 0.7%) in 2002/2003. A
approximately 4.3 million. In addition, imported      change in IRS policy to reintroduce DDT for
malaria is a significant problem in travellers        traditional style dwellings following the
returning from high malaria transmission areas        identification of Anopheles funestus resistant to
in African countries, notably Mozambique.             pyrethroids, and the introduction of artemisinin-
                                                      based combination therapy contributed
MALARIA CONTROL PROGRAMME (MCP)                       significantly to these malaria control successes.
The major strategies of the MCP in South Africa
are: vector control through Indoor Residual           However, malaria cases and deaths reported for
Spraying (IRS); early effective case management;      the 2003/2004 malaria season have shown an
disease surveillance; epidemic preparedness and       increase of 23% and 50% to 15 544 cases and
response; malaria advocacy and information,           150 deaths (case fatality rate 1%) respectively when

compared to the previous season. These increases             treatment and chemoprophylaxis policies. In
have largely been attributed to increased rainfall           South Africa chloroquine resistance in KZN and
and focal malaria outbreaks in the Limpopo                   later in Mpumalanga and Limpopo provinces
province and parts of KZN. The increase in the               necessitated a change to sulfadoxine-
number of deaths can be attributed to late                   pyrimethamine (SP) in 1988, 1997 and 1999
presentation of malaria patients and health system           respectively. The development of significant SP
failures, especially poor case management.                   resistance in KZN resulted in a further policy
                                                             change to artemether-lumefantrine (Coartem®)
The Lebombo Spatial Development Initiative                   in 2001 as first line treatment for uncomplicated
(LSDI) malaria project, driven by the Medical                Plasmodium falciparum infections.
Research Council, is showing excellent results
with major reductions in malaria cases in South              In order to halt the pattern of continued parasite
Africa, Mozambique and Swaziland. The spraying               resistance to sequential single drug therapy,
operations will extend to further zones in                   combination chemotherapy, including an
Mozambique and there are plans to introduce                  artemisinin derivative is recommended. Additional
combination therapy in Maputo province in the                benefits include an improved therapeutic
very near future. Inter-country and cross border             response, a decrease in malaria transmission and
malaria control initiatives are currently being              thereby greater cost effectiveness. The potential
strengthened with Angola and Zimbabwe.                       to delay anti-malarial resistance is a further
                                                             motivation for the widespread implementation of
CASE MANAGEMENT                                              artemisinin-based combination therapies.
The goal of the malaria control programme in                 Mpumalanga introduced a combination of SP plus
South Africa is to ensure that malaria cases do not          artesunate (Arsudar) in 2003 and artemether-
exceed one per thousand in the population at risk            lumefantrine will be introduced in Limpopo during
and to sustain a case fatality rate of less than 0.5%.       the 2004/2005 malaria season as first line
Key factors in the successful management of                  treatment for uncomplicated malaria. The
malaria cases are early and accurate diagnosis               artemisinin group of drugs are rapidly acting,
and urgent treatment using effective drugs. Major            highly effective and well tolerated. Resistance to
challenges are the non specific clinical pre-                date has not been demonstrated. These drugs
sentation of malarial disease, the rapid pro-                should always be used in combination with a
gression of disease in South African patients, all of        second effective drug to prevent recrudescence
whom could be considered malaria non-immune,                 and development of resistance. Sentinel sites to
and the development of parasite resistance to anti-          monitor drug efficacy and in-vivo resistance have
malarial drugs. Plasmodium falciparum accounts               been established in all three malaria transmission
for the majority of infections and all severe                provinces. Relatively higher costs of these
disease, although it is likely that there is an under-       artemisinin drugs are a major obstacle to their
estimate of the number of mixed infections. Non              introduction into resource poor, high transmission
falciparum malaria in South Africa is generally              countries, but public- private partnerships are
associated with mild illness, and chloroquine is             being forged to address this issue.
effective for treatment of acute disease. Primaquine
is needed to eradicate the latent hepatic stages.            Quinine remains highly effective for the treatment
                                                             of both uncomplicated and severe malaria, and
A high index of suspicion is the most important              the addition of doxycycline or clindamycin is
element in the diagnosis of malaria. Any person              recommended to ensure cure. Parenteral
resident in or returning from a malaria                      artemisinins, although highly affective for severe
transmission area who presents with fever, and/              malaria, are not currently available in South Africa.
or headache, rigors or a flu-like illness should be          The administration of artemisinins as artesunate
tested for malaria irrespective of the time of the           suppositories has been shown to be highly
year, or whether the person has taken                        effective in the treatment of patients with
chemoprophylaxis. The treatment of malaria is                moderately severe malaria.
based on a definitive diagnosis either by
examination of stained peripheral blood smears,              CHEMOPROPHYLAXIS
or by the use of rapid malaria tests which detect            The major focus of prevention of malaria is on
malaria antigen or parasite enzymes.                         the use of personal protective measures to
                                                             prevent mosquito bites. These measures include
DRUG POLICY FOR TREATMENT                                    the application of DEET containing repellents to
The ongoing development of parasite drug                     exposed skin, insecticide impregnated bednets,
resistance necessitates frequent updating of                 mats impregnated with insecticide, the wearing

of long trousers and socks, and the use of                  resistance and this regimen is no longer
screened windows and doors.                                 recommended first line. Atovaquone-proguanil
                                                            (Malanil®) has been recently registered as a
Chemoprophylaxis should be considered if visiting           chemo prophylactic in South Africa. It is highly
malaria transmission areas where the risk of                effective, relatively well-tolerated and is as an
acquiring malaria outweighs any potential serious           alternative option to mefloquine or doxycycline.
adverse drug reaction. The choice of chemo                  As atovaquone-proguanil is considered to be a
prophylactic drug should be individualised and              causal prophylactic, the drug needs to be taken
is dependent on patient factors such as age, co-            only for the duration of the malaria exposure and
morbidity, allergy, medication, pregnancy,                  for 7 days thereafter.
previous experience with the drug, duration of
the visit and drug resistance at the destination.           References
                                                            1.   National Department of Health, Pretoria., Guidelines for the
Weekly mefloquine or daily doxycycline are                       treatment of malaria in South Africa March 2003.
considered highly effective but a number of contra          2.   National Department of Health, Pretoria. Guidelines for the
                                                                 prevention of malaria in South Africa August 2002.
indications exist for their use. The efficacy of            3.   Barnes KI, Mwenechanya J, Tembo M, et al. Efficacy of rectal artesunate
                                                                 compared with parenteral quinine in initial treatment of moderately severe malaria
weekly chloroquine and daily proguanil has                       in African children and adults: a randomized study. The Lancet 2004; 363: 1598-
decreased due to widespread chloroquine

                                        TYPHOID FEVER
                         Karen Keddy, Enteric Diseases Reference Unit (EDRU), NICD

Typhoid fever is a systemic bacterial disease, charac-      THE ORGANISM
terised by an insidious onset of fever, malaise, relative   Salmonella typhi is a gram-negative bacillus. The
bradycardia, splenomegaly and a non-productive              nomenclature is confusing, as it is a serotype
cough. Constipation is commoner than diarrhoea              within S. enterica subspecies enterica (serotype
and a mild rash (rose spots) may be noted on the            Typhi), but because it only infects humans and is
trunk. The disease is caused by Salmonella typhi,           of major clinical and public health significance
less frequently by S. paratyphi A, B, or C, and has         compared with other salmonella serotypes,
significant epidemic and hence public health                common practice is to give it species status. It
potential. For this reason, it has been a notifiable        has the ability to become encapsulated (Vi
disease since 1919. Paratyphoid fever tends to be           antigen) and blood culture isolates may be
a less severe disease, with a lower case fatality rate.     agglutinated with anti-Vi antisera.

S. typhi is acquired via the faecal–oral route, most        DIAGNOSIS
frequently through contaminated water or foods.             Diagnosis primarily depends on the recovery of
The incubation period is between 1 and 3 weeks,             the organism from blood or bone marrow, or
depending on the infective dose. Patients remain            through serological diagnosis; specifically the
infective as long as they actively excrete the              Widal test is still widely used. The Widal may be
bacillus in their stool. In endemic areas attack            negative in up to 30% of cases. For clinicians to
rates decline with advancing age due to the                 rely on a diagnosis using the Widal test, they must
acquisition of immunity. In these areas, the peak           be familiar with the local population antibody titres
incidence is between the ages of 5 and 15 years.            to the O (somatic) and H (flagellar) antigens of
In areas of poor water supply, incidence rates              S. typhi as well as local resistance patterns of
may be 5 times higher than those of the rest of             the organism. Other disadvantages of the Widal
the country and in past years high endemicity was           are that two specimens are necessary to see a
noted in Limpopo, Mpumalanga, Eastern Cape                  change in antibody titre; seroconversion only
and Kwa-Zulu-Natal. The last major epidemic in              occurs after one to two weeks after the onset of
South Africa was noted in 1994 in Delmas,                   disease (table 1) and antibiotic resistance
Mpumalanga. It is note-worthy that as delivery of           patterns would not be recognised. For these
treated water improves in an area, the incidence of         reasons, the Widal has no definitive role in the
typhoid fever decreases. The incidence of the               diagnosis of typhoid fever in South Africa today.
disease and death rate over the last few years,
according to clinical notifications received by the         Newer serological tests are currently under
Department of Health in Pretoria, is reflected in           evaluation. Some of these are specific for IgM,
figures 1a and b.                                           and appear more specific even than culture.

However, even in these instances repeat                     including ampicillin, chloramphenicol and co-
specimens may be necessary and antimicrobial                trimoxazole. In 2004, the numbers of resistant
resistance patterns would not be elucidated.                isolates appear to be increasing. A worrying
                                                            feature is that resistance has been observed in
Blood culture remains the optimal method for                Eastern Cape, where the practice of using the
identification of typhoid fever. More than 80% of           Widal test for the diagnosis of typhoid fever is
patients will have the organism in their blood and          still common.
the optimum time for recovery of the organism is
after 7 to 10 days of fever. Bone marrow culture            Recent studies have shown that the
is the gold standard, but is more invasive, and             fluoroquinolones are highly effective in the
should be conserved for those patients who have             treatment of typhoid fever, given as short course
been previously treated or where the blood                  therapy, as is ceftriaxone. Both of these antibiotics
culture was negative, with a long history of illness.       have also shown better GIT clearance of the
Laboratory diagnosis using blood cultures usually           organism and patients treated with these are less
confirms the result within 48 hours, with antibiotic        likely to become long-term carriers. A second
susceptibilities taking a further 24 hours.                 advantage is these antibiotics decrease in-
Syndromic treatment should be started as soon               hospital time of the patient. Oral fluoroquinolones
as the blood culture is taken, depending on local           are the treatment of choice in patients if there
resistance patterns. Optimal times of diagnoses             are no contra-indications to this class of
depending on the clinical stage of disease are              antibiotics. It is important to note that fluoro-
indicated in table 1.                                       quinolone resistance in S. typhi has been
                                                            documented on the Indian subcontinent and
ANTIBIOTIC MANAGEMENT                                       there have been anecdotal reports of extended-
Antimicrobial resistance in S. typhi has been               spectrum beta-lactamase production from this
described in South Africa, but is found in the              area. Should multi-drug resistance continue to
minority of strains. Most of these isolates are from        emerge, it has been postulated that combination
northern KwaZulu-Natal. Until recently, the isolates        therapy with a fluoroquinolone and extended
received by the EDRU from other provinces, have             spectrum cephalosporins may become necessary.
been fully susceptible to all antimicrobials tested,        Appropriate current treatment regimens for South

 Table 1 : Yield of cultures and Widal test during the course of untreated typhoid fever.

               Incubation            Active                 Established        Convalescence          Late
               ↓                    invasion                 disease                               complications

  Time         Ingestion     Wk 1          Wk 2               Wk 3             Wk 4         Wk 5     Indefinite

  Blood        Negative             ←             80-90%             →         Negative unless continued disease
  cultures                                                                                  or relapse

  Stool        Transiently          Negative        ← 80% positive →            ←      50% →       Decreasing
  cultures      positive                                                              positive     incidence of
                                                                                                   positive cultures
                                                                                                   with time :
                                                                                                   20% at 2 mo
                                                                                                   3% at 1 yr

  Urine        Negative             Negative        ← 25% positive →             ← 10% →           Decreasing
  cultures                                                                            positive     incidence of
                                                                                                   positive cultures

  Bone         Negative             Negative       ← 80-90% positive →               Decreasing
  marrow                                                                            incidence of

  Widal        Negative          ← 20% →            ← 50% →                ← 80% positive →
  test                              positive            positive

  Table 2 : Treatment of uncomplicated typhoid fever

         Susceptibility                         Optimal Therapy                     Alternative effective drugs

         Fully sensitive                - Fluoroquinolone                           - Chloramphenicol
                                        - Third generation cephalosporin            - Ampicillin
                                                                                    - Trimethoprim-Sulphamethoxazole

         Multidrug resistance           - Fluoroquinolone                           - Azithromycin
                                        - Third generation cephalosporin

   Africa are listed in table 2. Drug dosages should              taken. It may be associated with nausea and can
  be tailored according to the age and weight of                  be taken by adults and children after the age of
  the patient.                                                    5 years. Travellers should be revaccinated
                                                                  annually. Herd immunity has been demonstrated,
  TYPHOID VACCINES                                                but it is theoretically contra-indicated in immune
  Currently there are three vaccines available for                suppressed individuals. The vaccine may be
  use in the prevention of typhoid fever. The old                 inactivated by concomitant use of antibiotics, and
  whole cell killed vaccine was highly effective, but             although theoretically there is no interference by
  due to the severity of side effects, compliance                 antimalarials, it is recommended that a three-day
  was poor. Subsequently two new vaccines, one                    interval be maintained between completion of
  based on the Vi antigen and the second a live                   vaccination and malaria prophylaxis.
  attenuated bacterial enteric vaccine, have been
  developed.                                                      Newer vaccines under development include Vi-
                                                                  conjugate candidates, which can be used in
  The Vi polysaccharide vaccine is given as a single              children under the age of two years, as well as
  subcutaneous or intramuscular dose. Protection                  newer live attenuated S. typhi candidates, based
  begins seven days after vaccination. The vaccine                on the deletion of virulence genes.
  is approved for persons over 2 years of age and
  protection lasts for at least 3 years.                          Current WHO recommendations for typhoid
                                                                  vaccination are targeted at travellers to areas that
  The live oral Ty21A vaccine is available as an                  are highly endemic for typhoid fever, inhabitants
  enteric-coated tablet and requires three doses                  of refugee camps, microbiologists, sewage
  two days apart on an empty stomach. It elicits                  workers and school children in areas where
  protection 10 to 14 days after the last tablet is               disease control is a priority.

                                                                 60                               Cases per 100 000 population
                                                                                                  No. of deaths
                                 No. of cases                    50

2000                                                             20

1000                                                             10

  0                                                               0


























  Figure 1a. Reported typhoid cases, Department of Health,        Figure 1b. Reported typhoid case incidence and total
  South Africa, 1985-2002 (Source: Epidemiological Com-           number of deaths, Department of Health, South Africa,
  ments, Department of Health, South Africa)                      1985-2002 (Source: Epidemiological Comments,
                                                                  Department of Health, South Africa and derived from
                                                                  Statistics SA).

  1. Department of Health. Typhoid fever in South Africa 1919-1994. Epidemiological Comments 1995: 22: 24-38.
  2. Department of Health. Epidemiological Comments 1995 - 2002.
  3. World Health Organisation. Background document: the diagnosis, treatment and prevention of typhoid fever. World Health
  Organisation, Geneva, 2003.
  4. World Health Organisation. State of the art of new vaccines: Research and Development. World Health Organisation, Geneva,


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