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Rev. sci. tech. Off. int. Epiz., 2006, 25 (3), 1153-1163
Contagious caprine pleuropneumonia
and Mannheimia haemolytica-associated
acute respiratory disease of goats
and sheep in Afar Region, Ethiopia
G. Shiferaw (1, 3), S. Tariku (2), G. Ayelet (2) & Z. Abebe (1)
(1) Department of Microbiology, Kombolcha Regional Veterinary Laboratory, P.O. Box 9, Kombolcha, Ethiopia
(2) National Veterinary Institute, P.O. Box 19, Debre Zeit, Ethiopia
(3) Department of Microbiology, Immunology and Parasitology, Faculty of Medicine, Addis Ababa University,
P. O. Box 9086, Addis Ababa, Ethiopia
Submitted for publication: 28 February 2005
Accepted for publication: 6 October 2006
Summary
In April 2002, an investigation into an outbreak of acute respiratory disease in
goats and sheep in Milae (Afar), Ethiopia was conducted. The investigation
involved 4 flocks (722 sheep and 750 goats in total) and comprised the disease
history, clinical and post-mortem examination, and microbiological analysis of
nasal swabs, lung lesions, and pleural fluid samples. Clinically diseased animals
exhibited severe respiratory distress, and necropsy of two of the goats
demonstrated fibrinous pneumonia, lung sequestra, and excessive accumulation
of straw coloured fluid in the thoracic cavity. Mannheimia haemolytica biotype T
was isolated from nine (six goats and three sheep) out of 23 nasal swabs (39.1%).
In the two necropsied animals Mycoplasma capricolum subsp.
capripneumoniae (Mccp) was isolated from the lungs, and Mannheimia
haemolytica biotype T was isolated from lung lesions and thoracic fluid. An
unidentified Mycoplasma species was isolated from the thoracic fluid of one of
the goats. Pseudomonas aeruginosa was isolated from a lung sequestrum of one
of the necropsied goats. In vitro antimicrobial susceptibility test results indicated
that two (33.3%) of the six M. haemolytica isolates that were tested were
resistant to ampicillin and penicillin G, three (50%) to tetracycline, four (66.7%) to
oxacillin, five (83.3%) to erythromycin, and six (100%) to clindamycin.
Pseudomonas aeruginosa was resistant to all of the different classes of
antimicrobials that were tested. Pleuropneumonia caused by Mccp, and
secondary complications caused by M. haemolytica and the other unidentified
Mycoplasma species, were confirmed as the cause of the outbreak. Morbidity
was not associated with the species of animals affected (P > 0.05); however,
mortality was significantly higher in goats than sheep (P < 0.05).
Keywords
Acute respiratory disease – Contagious caprine pleuropneumonia – Ethiopia – Goat –
Mannheimia haemolytica biotype T – Mycoplasma capricolum subsp. capripneumoniae –
Pseudomonas aeruginosa – Sheep.
1154 Rev. sci. tech. Off. int. Epiz., 25 (3)
Introduction occurred in Milae District of Afar Region, Ethiopia. The
outbreak generated media attention (23), and in response
to the request from regional authorities, the outbreak was
Small ruminants in Africa represent 21% of the world’s
investigated. This study describes the findings of the
small ruminant population. The population of sheep in
investigation.
Africa represents 17% of the total world sheep population,
while goats represent 30% of the world goat population
(9). Ethiopia possesses an estimated 11,438,200 and
9,620,800 heads of sheep and goats, respectively (6),
equivalent to 2,105,900 tropical livestock units (TLU)
Materials and methods
(1 TLU = 250 kg; 1 sheep/goat = 0.1 TLU). Small
General approach to the investigation
ruminants in Africa are reared in different livestock
production systems ranging from crop/livestock mixed A field investigation was initiated on 2 April 2002 in Milae
systems in the highlands, to pastoral systems in the arid District. As part of the investigation, the geographical area
lowlands. Sheep and goats play a significant role in the and the history of the disease were assessed, clinical and
nation’s economy. Meat and milk are major sources of post-mortem examinations were carried out, and samples
protein, and hides, live animals, and carcasses account for from both live and dead animals were taken for laboratory
a significant proportion of exports. In Ethiopia, sheep and analysis. Four flocks were clinically examined, and two
goats are affected by many infectious and parasitic diseases. goats from one of these flocks, both of whom had severe
Infectious diseases of small ruminants such as peste des respiratory distress, were provided by the owner for post-
petits ruminants (PPR) (10), sheep and goat pox, mortem examination. The owners of all four flocks were
contagious caprine pleuropneumonia (CCPP) (7, 10, 19, interviewed (individually and in a group) using a checklist
21, 27), brucellosis, pneumonic pasteurellosis/ based on the format used by the World Organisation for
mannheimiosis and maedi-visna (2) have been reported. Animal Health (OIE) in their monthly outbreak reports
Considerable losses occur frequently as a result of (the list includes elements such as species of animal
outbreaks of such infectious diseases; however, both the affected, number of cases and deaths, source of the disease,
outbreaks and losses from such outbreaks are not well vaccination history, previous treatment, etc).
documented. Diseases caused by parasites such as Fasciola,
lungworms, Haemonchus and mange mites also hinder the
full production potential of these resources. Study area
The study area was situated within Milae District of Afar
The classical Mycoplasma mycoides cluster contains
Region. The district is located 135 km east of Kombolcha
M. capricolum subsp. capripneumoniae (Mccp),
and about 500 km north-east of Addis Ababa along the
M. capricolum subsp. capricolum, M. mycoides subsp. capri,
road to Djibouti. The outbreak area was geographically
M. mycoides subsp. mycoides type LC (MmmLC),
positioned at 11°24’476”N and 040°45’439”E at an
M. mycoides subsp. mycoides type SC, and Mycoplasma sp.
altitude of 703 metres above sea level (Fig. 1). The region
bovine serogroup 7 (19). Many Mycoplasma species are
is within an arid agro-ecological zone and is prone to
capable of infecting goat and sheep lungs and inducing
recurrent drought due to erratic rainfall. Multi-species
pleuropneumonia. Contagious caprine pleuropneumonia
pastoralism is the preferred and most practiced system of
is a severe contagious disease of goats caused by Mccp.
livestock production. Local breeds of goats and sheep are
Unlike true CCPP, which is confined to the thoracic cavity,
relatively resistant to the harsh conditions of the area. They
the disease caused by MmmLC, M. mycoides subsp. capri,
serve as a source of milk and meat for the local households
and M. capricolum subsp. capricolum is characterised by
and live animals are sold to generate cash whenever the
prominent lesions in other organs and/or parts of the body
need arises. The district has an estimated 140,976 goats
in addition to the thoracic cavity (26). Mycoplasma
and 70,488 sheep (Afar Bureau of Agriculture, personal
capricolum subsp. capripneumoniae was first isolated and
communication). Small ruminants are herded and housed
shown to cause CCPP in Kenya. It has subsequently been
separately from other species of animals.
isolated in Sudan, Tunisia, Oman, Turkey, Chad, Uganda,
Ethiopia, Niger, Tanzania, Eritrea, and the United Arab
Emirates (26). In Ethiopia, CCPP occurs in most of the
extensive goat rearing areas, namely, Afar, Borana, Omo Samples collected
Valley, West Gojjam, and in the lowlands of Tigray (21, Samples collected from live animals (nasal swabs, serum,
27). The first case was reported from Assosa District, and whole blood) and from the two necropsied goats (lung
Western Ethiopia (21). lesions, pleural fluid, and tracheal swabs) were placed in
sterile bottles. Eye swabs were also collected from animals
In the months of February and March 2002, an outbreak showing signs of keratoconjunctivitis. Tubes containing
of a contagious acute respiratory disease of sheep and goats tryptone soya broth were immediately inoculated with
Rev. sci. tech. Off. int. Epiz., 25 (3) 1155
Study Area
Towns
Lakes
Regional Boundary
Elevation
Metres above sea level
High: 4517
Low: -236
Fig. 1
Map of Ethiopia indicating the outbreak area
nasal swab specimens for the isolation of Mannheimia. All characteristics and the results of the biochemical tests,
of the samples were frozen (–20°C) and transported on ice isolates were classified and grouped according to genus
to the regional government laboratory in Kombolcha and species.
(within a day). In addition, samples of lung lesions and
pleural fluid were transported to a laboratory in Debre Zeit In vitro antimicrobial susceptibility
(within two days) and stored at –20°C until processed. The agar disc diffusion technique using Mueller-Hinton
medium as described by Jorgenson et al. (12) was applied
to Mannheimia isolates from two lung samples and four
Laboratory diagnosis nasal swabs, and to Pseudomonas isolated from one lung
sample. Escherichia coli 25922 (ATCC) obtained from the
Bacteriological analysis
National Health and Nutrition Research Institute was used
Nasal swabs (from 14 live goats and 9 live sheep) and as a quality control. Tests were considered to be valid when
autopsy samples collected from the necropsied goats were results for the reference strain were within the expected
subjected to conventional bacteriological examination in range specified by the Clinical and Laboratory Standards
the regional laboratory (Kombolcha). Prior to culture, the Institute (CLSI [formerly NCCLS]). Pure colonies of
samples were enriched via inoculation into tryptone soya bacteria were grown in tryptone soya broth. Bacterial
broth (Oxoid, United Kingdom [UK]) and incubation at suspensions were prepared by matching the samples to
37°C. The enriched samples were then used to inoculate 0.5 McFarland turbidity standards and were then used to
plates of blood and MacConkey agar (Oxoid, UK). inoculate Mueller-Hinton media. Antimicrobial discs
Bacterial growths were subcultured to obtain pure (ampicillin, penicillin G, oxacillin, erythromycin,
colonies, which appeared as Gram-negative short rods after tetracycline, clindamycin, and sulphafurazole; Oxoid, UK)
Gram staining. On blood agar, the colony characteristics of were distributed on the inoculated plates using an
pure cultures were examined and recorded. On antimicrobial dispenser and the plates were incubated at
MacConkey agar, colony growth and lactose fermentation 37°C. Results were read after an incubation period of 18 to
properties were observed and recorded. The following 24 hours. Interpretation was made using interpretative
biochemical tests were subsequently performed: oxidase, standards described by Jorgenson et al. (12), which are
catalase, indole, hydrogen sulphide, urease, glucose, based on CLSI performance standards for antimicrobial
sucrose, salicine, and trehalose. Based on growth susceptibility testing (18). The zone diameter cut-off value
1156 Rev. sci. tech. Off. int. Epiz., 25 (3)
provided for Gram-negative bacteria was used to evaluate affected in each of the flocks. The disease covered a large
susceptibility to ampicillin and penicillin, a cut-off value of geographical area, indicating a high transmission rate. The
14 mm was used to determine susceptibility to oxacillin, flocks were not vaccinated for CCPP and clinically ill
and the cut-off value provided for sulphonamides was used animals and suspected cases had been treated with
to assess susceptibility to sulphafurazole (12). oxytetracycline, which seemed to reduce morbidity and
mortality (although the survey team was unable to observe
Mycoplasma isolation the animals for an extended period of time).
Lung and thoracic fluid specimens collected from the two
More than 30,000 animals were at risk. Out of a total of
necropsied goats were submitted to the National Veterinary
722 sheep and 750 goats from four flocks, the morbidity
Institute (Debre Zeit, Ethiopia) for Mycoplasma isolation
rate was 57% and 53% and the mortality rate was 22% and
and characterisation. Mycoplasma was isolated using
32% in sheep and goats, respectively. At the time that the
Thiaucourt’s medium, which contained Bacto-PPLO broth
present investigation was undertaken, the case fatality rate
without crystal violet (Difco Laboratories), inactivated
had reached 38% in the sheep population and 59% in the
horse serum, yeast extract, glucose, sodium pyruvate,
goat population.
ampicillin, and thallium acetate. Tissues were
homogenised in broth media using a sterile mortar and
pestle. The homogenate was then streaked onto agar plates
and the seeded agar plates were incubated at 37°C in a CO2 Clinical signs
incubator for 14 days. The plates were checked daily for Both species developed the disease, though clinical signs
the appearance of colonies. Pure colonies were selected were more severe in goats. Fever, loss of appetite and
and biochemical tests for the breakdown of glucose, condition, hyperpnoea, expiratory grunt, mucoid nasal
hydrolysis of arginine, reduction of tetrazolium chloride, discharge, and open-mouth breathing were observed in
phosphatase activity, and arginine hydrolysis were carried clinically sick animals (Fig. 2). In one flock, a few of the
out on each isolate. Isolated Mycoplasma colonies were also animals had keratoconjunctivitis with corneal opacity and
examined by growth inhibition and dot-blot tests four of the animals had diarrhoea.
using Mccp monoclonal antibodies (Centre de coopération
internationale en recherche agronomique pour
le développement - Elevage et médecine vétérinaire
tropicale [CIRAD-EMVT]) (26).
Virus isolation and serology for
antibodies to peste des petits ruminants virus
A portion of the specimens were also submitted for virus
isolation to the Virology Laboratory at the National
Veterinary Institute. Eighty-seven samples of sera were sent
to the National Animal Health Research Center in
Sebeta, Ethiopia, where they were tested for PPR
using a competitive enzyme-linked immunosorbent
assay (cELISA).
Statistical analysis
Data were presented using descriptive statistics and the Chi
square test was used to test the null hypothesis of equality
of clinical cases and deaths, resulting from the disease,
between goats and sheep.
Results
Disease history
The outbreak was first reported in February. Herdsmen Fig. 2
claimed the disease was associated with a shortage of feed Nasal discharge and mouth breathing due to respiratory
due to the long dry season. Both goats and sheep were distress
Rev. sci. tech. Off. int. Epiz., 25 (3) 1157
Post-mortem findings Bacteriological analysis
Necropsy examinations were performed on two goats Bacterial isolates were identified from the various samples
provided by the owner of one of the flocks. Inspection was based on growth characteristics, Gram staining, and
concentrated on the thoracic cavity. Lesions were mainly primary and secondary biochemical test results.
localised in one lung in both of the animals; the gross
pathological observations were as follows: excess straw
Nasal swab
coloured fluid in the thoracic cavity, a red area of
consolidation, slightly distended intralobular septa, pleural Using a variety of different biochemical tests the following
adhesion, and two encapsulated foci containing whitish results were obtained: 9 of the 23 nasal swabs
material (sequestra) (Figs 3a to 3d). (39.1%) were positive for Mannheimia haemolytica biotype
Fig. 3a Fig. 3c
Pneumonic lung with fibrin deposition Lung with sequestra
Fig. 3d
Fig. 3b Deposits of fibrin in the visceral pleura and excessive straw
Lung lesion localised in one lung coloured fluid in the thoracic cavity
1158 Rev. sci. tech. Off. int. Epiz., 25 (3)
T (six from goats and three from sheep), 5 failed to be Mycoplasma investigation
positive for M. haemolytica due to the results of one of the
biochemical tests, and 9 (39.1%) were positive for Bacillus Mycoplasma was isolated from lung lesions and thoracic
soecies. fluid collected from the two necropsied goats. After cloning
and subculture, three isolates (two from the lung and one
from the pleural fluid) were further identified to the
Lung
species level using biochemical tests and growth inhibition
Mannheimia haemolytica biotype T was isolated from lung and dot-blot tests specific for Mccp. The isolates were
lesions from both of the necropsied goats. Pseudomonas positive for glucose fermentation and reduction of
aeruginosa was isolated from lung sequestra and exhibited tetrazolium chloride, negative for phosphatase activity, and
the following characteristics: growth on MacConkey agar, negative for the hydrolysis of arginine. Two of the isolates
lactose fermentation negative, oxidase positive, indol (from the lungs of both of the goats) were inhibited with
doubtful, and glucose, sucrose, and salicine positive. Mccp hyperimmune serum and were positive for the dot-
Pseudomonas aeruginosa colonies produced a blue pigment blot test, while the isolate from the pleural fluid of one of
on Mueller-Hinton agar and appeared red in colour in the goats was not inhibited by Mccp hyperimmune serum
brilliant green agar. and was negative for the dot-blot test. Hence, from one of
the goats, only Mccp was isolated, while from the other
Pleural fluid goat, Mccp was isolated from the lung and another
Mycoplasma, which could not be identified, was isolated
Mannheimia haemolytica biotype T was isolated from
from the pleural fluid.
pleural fluid collected from the two necropsied goats.
Tracheal swab Virus isolation and peste des petits ruminants
Bacillus species were isolated from tracheal swabs collected serology
from the necropsied goats.
No viruses were isolated and one animal was sero-reactive
for PPR using the cELISA test.
Eye swab
Staphylococcus and Bacillus species were isolated from eye
swabs taken from animals showing signs of
keratoconjunctivitis. Discussion
Based on clinical, necropsy, laboratory, and
epidemiological findings, clinical disease was diagnosed as
In vitro antimicrobial susceptibility CCPP, which is caused primarily by Mccp with secondary
Mannheimia isolated from two lung and four nasal swab .
invasion by M. haemolytica biotype T and P aeruginosa.
samples, and Pseudomonas isolated from one lung sample, Mycoplasma capricolum subsp. capripneumoniae was
were used for in vitro antimicrobial susceptibility tests. The isolated from lung lesions of both of the necropsied goats;
results are presented in Table I. however, the species of Mycoplasma isolated from the
Table I
Results of antimicrobial susceptibility tests
Mannheimia haemolytica Pseudomonas aeruginosa
Antimicrobials Susceptible no. Intermediate no. Resistant no. Susceptible no. Intermediate no. Resistant no.
of isolates (%) of isolates (%) of isolates (%) of isolates (%) of isolates (%) of isolates (%)
Ampicillin (10 µg) 4 (66.7) 2 (33.3) 1 (100)
Penicillin G (10 IU) 3 (50) 1 (16.7) 2 (33.3) 1(100)
Oxacillin (1 µg) 2 (33.3) 1 (16.7) 4 (66.7) 1 (100)
Erythromycin (15 µg) 2 (33.3) 1 (16.7) 5 (83.3) 1 (100)
Tetracycline (30 µg) 4 (66.7) 3 (50.0) 1 (100)
Sulphafurazole (100 µg) 2 (33.3) 1 (100)
Clindamycin (2 µg) 6 (100.0) 1 (100)
Rev. sci. tech. Off. int. Epiz., 25 (3) 1159
pleural fluid of one of the goats could not be identified. Pneumonia in sheep and goats, primarily caused by
Small ruminant respiratory disease often has a multi- Mycoplasma, is commonly complicated by
factorial origin (4), which may have been the case in this Pasteurella/Mannheimia (4), which was observed in this
outbreak. Mycoplasma capricolum subsp. capripneumoniae outbreak. The Mannheimia species/biotype isolated in
caused the primary infection, at least in the goat upper respiratory tract (nasal swab) and lower respiratory
population. Clinical disease may have occurred as a result tract (lung and pleural fluid) samples was M. haemolytica
of a new infection or may have been the result of a flare-up biotype T. Isolates from both anatomic sites showed a
of subclinical infection stimulated by environmental stress. similar antimicrobial susceptibility pattern. In a study
During the outbreak period, the weather conditions were undertaken in calves with clinical signs of respiratory
harsh (extreme ambient temperature) and there was a .
disease, M. haemolytica and P multocida isolates obtained
severe feed shortage. Primary infection of the lower from nasal and transtracheal swabs showed similar
respiratory tract with Mycoplasma and Bordetella ribotyping and antibiotic susceptibility patterns (5). The
parapertussis can increase the susceptibility of sheep and investigation suggested that a nasal swab culture can be
goats to secondary M. haemolytica infection (4). Stress, predictive of bacterial pathogens within the lung and could
induced by factors such as heat, overcrowding, exposure to be used to determine antibiotic susceptibility when the
harsh weather conditions, poor ventilation, handling, and isolates are from acutely ill animals (5). A study
transport, is a major predisposing factor (4). undertaken in the highlands of Ethiopia suggested that
cases of pneumonic pasteurellosis were mainly caused by
.
M. haemolytica species (unpublished data, F Kebede and
Gross pathological observations were consistent with CCPP;
G. Shiferaw).
however, the sequestra which were observed on necropsy are
not a common characteristic of CCPP. Kusiluka et al.
In vitro antimicrobial susceptibility test results could be
demonstrated the concurrent presence of sequestra and
used as preliminary information for further monitoring.
M. capripneumoniae and M. mycoides subsp. mycoides in an
Most interpretive criteria used to categorise veterinary
outbreak of CCPP in Tanzania (14). Wesonga et al. reported
pathogens as susceptible or resistant to antimicrobials in
chronic pleuropneumonia with sequestra formations on
vitro are based on data obtained from human pathogens
necropsy at days 82 and 126 post-infection in goats
and pharmacokinetics of drugs used in humans (20). The
experimentally infected with Mccp (25).
validity of these criteria when used in animal pathogens is
questionable (24). From the six M. haemolytica isolates
The present outbreak involved both sheep and goats; tested, all were resistant to clindamycin. Fifty percent of
however, classical CCPP is described only in goats. A the isolates were resistant to tetracycline and 33.3% were
possible explanation for the occurrence in sheep in this resistant to penicillin and ampicillin, which is indicative of
outbreak is the presence of another pathogenic Mycoplasma a serious condition. Tetracycline (oxytetracycline) is a
which was capable of causing disease in both species of common and widely used antimicrobial for treatment of
animals (11, 22). Most of such Mycoplasma organisms pneumonic as well as other infectious diseases in small
produce mastitis, arthritis, keratitis, pneumonia, and ruminants and other farm animals. Penicillin is the most
septicaemia, which present as single conditions or in commonly available antimicrobial in Ethiopia and is the
combination (1, 22, 26). In this particular outbreak the front-line drug for treatment of infectious disease in all
pneumonic conditions were predominant, though animals species of livestock.
in one of the flocks also exhibited keratitis and diarrhoea.
The presence of lesions in other parts of the body Pseudomonas aeruginosa was isolated from lung sequestra
(a characteristic of disease caused by members of the from one of the necropsied goats and was found to be
M. mycoides cluster other than Mccp) may have been resistant to the spectrum of antimicrobials tested.
overlooked during necropsies and clinical examinations, Pseudomonas is an opportunistic organism and most
which were concentrated on the thoracic cavity. The infections with this organism have been localised to the
number of cases of the disease (morbidity) had no respiratory tract and occur in patients with underlying
association with the species of animal (P > 0.05), while the pulmonary disease (13, 17). Pseudomonas is considered to
severity of the disease (mortality) was significantly higher be a true pathogen when it is isolated from a sterile site
in goats than sheep (P < 0.05). Absence of post-mortem (13), and in this particular outbreak was not considered to
examination, bacteriology analyses, and specific be an important pathogen because it was isolated from a
investigation for Mycoplasma in the lungs of the sheep lung lesion of only one goat. Had the isolated Pseudomonas
made it very difficult to determine the primary cause of been classified as a significant pathogen, treatment of the
infection in sheep. However, it should be noted that Mccp infection could have been potentially frustrating since the
and antibodies to Mccp have been reported in pneumonic bacterium is typically resistant to multiple classes of
sheep in outbreaks of CCPP (3, 8), and, therefore, antimicrobial agents (13, 17), which was demonstrated by
Mccp could be the primary cause of disease seen in sheep the in vitro susceptibility results in this study. In addition,
in this outbreak. susceptible organisms can become resistant during therapy
1160 Rev. sci. tech. Off. int. Epiz., 25 (3)
due to the production of antibiotic inactivating enzymes and authority at various levels, has to be implemented to
(e.g. -lactamases), or through mutations in the genes control endemic diseases in these areas.
coding the outer membrane pore proteins, or by the
transfer of plasmid-mediated resistance from a resistance This study demonstrated the presence of Mccp and
organism to a susceptible one (17). M. haemolytica in a single outbreak in which both goats
and sheep were clinically affected, indicating the necessity
This study indicated the emergence of strains of animal for strong surveillance based on laboratory isolation and
pathogens resistant to commonly used antimicrobials. identification of infectious organisms. There is a need for
Further investigation on the clinical efficacy of the development and standardisation of rapid, inexpensive
antimicrobials and the impact of emerging resistant strains diagnostic tests for primary screening in the field prior to
of animal pathogens on human health is required. confirmatory laboratory diagnosis as part of surveillance
and control programmes. Promising experimental results
The interaction of a number of factors can predispose have been reported using latex agglutination tests (capsular
animals to acute respiratory disease. The reduction of polysaccharide antigen and antibody detection tests)
stressful conditions (e.g. provision of supplementary feed (15, 16).
during periods of drought) and the immunisation of flocks
against endemic diseases associated with the respiratory
disease complex (CCPP, PPR, parainfluenza, and
M. haemolytica) are important elements of any preventive Acknowledgements
herd health programme. The primary method of We would like to thank Dr Tsegaw Fentie, former Head of
containing the outbreak was the mass treatment of infected the Kombolcha Regional Veterinary Laboratory, for
flocks using antimicrobials (oxytetracycline), which helped arranging the field visit to undertake the present
to reduce morbidity and mortality. Although alternative investigation. We are indebted to Dr Lakemariham Yigezu
options to reduce the mortality of the flocks were of the National Animal Health Research Institute (Sebeta,
unavailable, caution should be exercised in the mass Ethiopia) for analysis of the sera for PPR. Drs. Amsalu
application of antimicrobials as there is a risk of creating a Demessie and Girma Abeto are also appreciated for their
pool of carriers and/or selecting resistant pathogens. encouragement. Last but not least, we would also like to
Pastoralists need to be encouraged and supported to apply thank Mr Atsemachew Bizawerk from the International
self-imposed quarantine measures. An early detection, Livestock Research Institute for providing the map
early warning, and early reaction system, which requires of Ethiopia.
the involvement of stock owners and veterinary personnel
Pleuropneumonie contagieuse caprine
et maladie respiratoire aiguë associée à Mannheimia haemolytica
des ovins et des caprins dans la région d’Afar, Ethiopie
G. Shiferaw, S. Tariku, G. Ayelet & Z. Abebe
Résumé
En avril 2002, une enquête a porté sur un foyer de maladie respiratoire aiguë
apparu chez les caprins et les ovins à Milae (Afar), en Ethiopie. Une anamnèse,
des examens cliniques et post-mortem, ainsi qu’une analyse microbiologique
des écouvillonnages nasaux, des lésions pleurales et des prélèvements de
liquide pleural ont été réalisés dans le cadre de l’enquête. Les animaux atteints
de signes cliniques de maladie présentaient une détresse respiratoire sévère et
l’autopsie de deux des caprins a montré l’existence d’une pneumonie fibrineuse,
de séquestres pulmonaires et d’une accumulation excessive de liquide jaune
Rev. sci. tech. Off. int. Epiz., 25 (3) 1161
paille dans la cavité thoracique. Mannheimia haemolytica T a été isolé à partir
de 9 (6 caprins et 3 ovins) écouvillonnages nasaux (39,1 %). Mycoplasma
capricolum sous-espèce capripneumoniae (Mccp) a été isolé dans les poumons
et Mannheimia haemolytica T dans les lésions pulmonaires et le liquide
thoracique de deux caprins autopsiés. Une espèce de mycoplasme non
identifiée a été isolée dans le liquide thoracique de l’un des caprins.
Pseudomonas aeruginosa a été isolé dans un séquestre pulmonaire de l’un des
caprins autopsiés. Les résultats des tests de sensibilité aux antimicrobiens
réalisés in vitro ont indiqué que deux (33,3 %) des six souches de M. haemolytica
étaient résistantes à l’ampicilline et à la pénicilline G, trois (50 %) à la
tétracycline, quatre (66,7 %) à l’oxacilline, cinq (83,3 %) à l’érythromycine, et six
(100 %) à la clindamycine. Pseudomonas aeruginosa était résistant à toutes les
classes d’antimicrobiens testées. Il a été confirmé que la pleuropneumonie due
à Mccp, et que les complications causées par M. haemolytica et l’autre espèce
de mycoplasme non identifiée étaient à l’origine du foyer. La morbidité n’était pas
associée à l’espèce animale touchée (P > 0,05) ; par contre, la mortalité était
significativement plus élevée chez les caprins que chez les ovins (P < 0,05).
Mots-clés
Caprin – Ethiopie – Maladie respiratoire aiguë – Mannheimia haemolytica T –
Mycoplasma capricolum subsp. capripneumoniae – Ovin – Pleuropneumonie contagieuse
caprine – Pseudomonas aeruginosa.
Pleuroneumonía contagiosa caprina y enfermedad
respiratoria aguda asociada a Mannheimia haemolytica
en ovejas y cabras de la región de Afar (Etiopía)
G. Shiferaw, S. Tariku, G. Ayelet & Z. Abebe
Resumen
Los autores describen una investigación realizada en abril de 2002 sobre un
brote de enfermedad respiratoria aguda que afectó a ovinos y caprinos de la
zona de Milae, Afar (Etiopía). Amén de estudiar la historia de la enfermedad, se
practicaron exámenes clínicos y post-mortem y análisis microbiológicos de
exudados nasales, lesiones pulmonares y muestras de líquido pleural. Los
ejemplares clínicamente afectados mostraban graves trastornos respiratorios,
y en dos cabras sometidas a necropsia se observó neumonía fibrinosa,
secuestro pulmonar y excesiva acumulación en la cavidad torácica de un líquido
amarillento. En 9 de los exudados nasales (un 39,1%), 6 de cabra y 3 de oveja, se
aisló Mannheimia haemolytica T, microorganismo también presente en las
lesiones pulmonares y el líquido torácico de las dos cabras objeto de necropsia,
en cuyas muestras de pulmón se aisló además Mycoplasma capricolum subsp.
capripneumoniae (Mccp). En el secuestro pulmonar de una de ellas se detectó
asimismo la presencia de Pseudomonas aeruginosa. Por otro lado, a partir
del líquido torácico de una cabra se aisló una especie no identificada
1162 Rev. sci. tech. Off. int. Epiz., 25 (3)
de micoplasma. Los resultados del antibiograma pusieron de manifiesto que dos
(33,3%) de las seis cepas aisladas de M. haemolytica eran resistentes
a la ampicilina y la penicilina G, tres (50%) a la tetraciclina, cuatro (66,7%) a la
oxacilina, cinco (83,3%) a la eritromicina y seis (100%) a la clindamicina.
Pseudomonas aeruginosa era resistente a todas las clases de antimicrobianos
utilizadas. Se confirmó que el origen del brote residía en la pleuroneumonía
causada por Mccp y en las complicaciones secundarias debidas
a M. haemolytica y a la otra especie de micoplasma no identificada. Aunque la
tasa de morbilidad no dependía de la especie afectada (P > 0,05), la mortalidad
resultó significativamente más alta en cabras que en ovejas (P < 0,05).
Palabras clave
Caprino – Enfermedad respiratoria aguda – Etiopía – Mannheimia haemolytica T –
Mycoplasma capricolum subsp. capripneumoniae – Ovino – Pleuroneumonía contagiosa
caprina – Pseudomonas aeruginosa.
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