and case fatality, negative avian cholera test result poultry resellers and markets contributed to spread of the outbreak, while vaccination was protective. 14 ...
Avian Newcastle disease: a farm case-control study in Mananjary, Madagascar, July 2015 – March 2016 N.P. Razafindraibe, M.A. Andriamananjara, M. Biarmann, P.S. Fenozara, A. Halm, M. Tajding, F. Ravaomanana, O.F. Maminiaina, H. Razafimandimby, E. Cardinale, H. Rasamoelina-Andriamanivo.
Introduction Newcastle disease (ND) avian paramyxovirus, incubation 3 days to 2 weeks
typical internal lesions : petechia or haemorrhage in proventriculus and in ceacal tonsil highly contagious viral disease affecting poultry, major constraint for village aviculture worldwide high morbidity and mortality, vaccine available transmitted via aerosols, birds, fomites, visitors
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Introduction Madagascar 2/3 of rural population practice poultry farming economic loss : 8.6 million £ per year 80-100% of avian disease outbreaks in rural settings due to ND most cases in September, October, November
waterfowl also affected: rare in the literature 3
Signal Dec 2015, suspected ND cases reported through Madagascar’s Animal Diseases Surveillance (MADSUR) network
Jan-March 2016, 50% increase in number of cases reported
Investigation to describe the outbreak, identify associated factors and to inform control measures
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Methods Study area: district of Mananjary
Study design: farm case-control Definitions Farm-case • a farm in Mananjary with • at least two sick or dead animal presenting at least two of: diarrhoea, respiratory, nervous symptoms, swollen head, prostration, between July 2015 and March 2016
Farm-control = all “healthy” farms with no sick or dead animals in the same villages 5
Methods Data collection identification of affected farms via veterinarians, their agents, village chiefs specimen taken from sick and dead animals: brain, tracheal & cloacal swabs autopsy of sick and alive animals
Interviews of farmers (farm-cases & -controls) number of sick and dead poultry symptoms & lesions, disease onset date poultry supply origin and farm management
farm level
ND vaccination 6
Methods Data analysis description of the outbreak and calculation of morbidity, case fatality OR, 95% CI
logistic regression, variable inclusion if p ≤ 0.05
Laboratory test for ND virus (PCR) and avian cholera bacteria (bacteriology) 7
Results 75% (15/20) villages affected proportion of farm-cases per village: 26% (6/23) to 85% (51/60)
252 farms interviewed: 178 farm-cases, 74 farm-controls
attack rate: 69% (3149/4550 animals in affected farms) case fatality: 92% (2896/3149 animals)
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Farm-cases of Newcastle disease (N=178), by date of onset, Mananjary Madagascar, July 2015 – March 2016
beg: beggining of the month mid: middle of the month end: end of the month
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Clinical signs in farm-cases (n=178), Mananjary Madagascar, July 2015 – March 2016 Symptoms
Number of farms (n=178)
%
Prostration
134
76
Twisted neck
92
52
Diarrhoea
82
46
Viscous slime
80
45
Legs necrosis
32
18
Nasal discharge
29
16
Paralyzed wings
29
16
Coughing
27
15
Big head
14
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Post-mortem lesions: petechia in proventriculus and in caecal tonsil Laboratory results: negative for cholera, pending for ND PCR kits stock rupture 10
Farm management
252 interviewed farmers 67% (169) sold corpses of deceased poultry to restaurants 68% (172) liquidated sick animals on the market 39% (99) famers breed poultry & waterfowl 57% (56) of them host the two in the same place during the night
36% (91) vaccinated their poultry
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Farm-cases and –controls of Newcastle disease by risk factor, Mananjary Madagascar July 2015 – March 2016 (n= 252) Variables
Number Number Adjusted farm-cases farm-controls OR (n=178) (n=74)
CI (95%)
Vaccination YES NO
39 139
52 22
0.1
0.1 – 0.3
Poultry purchase on market YES NO
109 69
28 46
2.9
1.5 – 5.7
Use poultry resellers YES NO
139 39
39 35
3.1
1.6 – 6.2 12
Limitations no individual data for symptoms and risk factors vaccination coverage potentially under-estimated laboratory results pending
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Conclusion ND outbreak based on symptoms, observed lesions, high attack rate and case fatality, negative avian cholera test result poultry resellers and markets contributed to spread of the outbreak, while vaccination was protective
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Recommandations educate breeders about risk of buying poultry on the market and poultry resellers’ visits during outbreak periods isolation of new poultry for two weeks separation of chickens and waterfowl overnight
burial of corpses of dead poultry regular poultry vaccination
reinforce vaccination campaigns
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Acknowledgments Ministry of Agriculture and Livestock National Veterinary Service Private veterinarian in Mananjary and their agents Farmers in Mananjary district National Veterinary Diagnostic Laboratory Department of Zootechnics and Veterinary Research EpiConcept Project funded by the Veille Sanitaire Project in the frame of the SEGA One Health Network- Indian Ocean Commission
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Thank you
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Study area Madagascar (XX regions, YYY districts) Mananjary district (XX municipalities, YYY neighbourhoods) Mananjary municipality (XX neighbourhoods, YYY farms) 20 neighbourhoods: 15 affected
692 farmers interviewed about ND presence 252 interviewed for case-control study
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Waterfowl affected • 968 waterfowl : 642 sick (morbidity: 66%), 520 dead (case fatality: 81%)
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