Longitudinal Study of Avian Influenza and Newcastle Disease in Village Poultry, Mali, 2009-2011.

Newcastle disease (ND) is endemic in West Africa, which has also experienced outbreaks of highly pathogenic avian influenza (AI) H5N1 since 2006. We aimed to estimate the prevalence and incidence of AI and ND in village poultry in Mali and to identify associated risk factors. A longitudinal serologic study was conducted between November 2009 and February 2011 using ELISA commercial kits to detect antibodies. Sera (5963) were collected from 4890 different poultry. AI was rare, with a seroprevalence of 2.9% (95% confidence interval [CI] 2.3-3.5) and a seroincidence rate of 0.7 birds per 100 bird-months at risk (95% CI 0.4-1.0). AI antibodies were short lived, with a seroreversion rate of 25.4 birds per 100 bird-months at risk (95% CI 19.0-31.7). Risk factors for AI were limited: temporal variation occurred, but proximity to a water body was a risk factor only when large populations of wild waterbirds were present. ND was very common, with seroprevalence of 68.9% (95% CI 61.9-76.0) and a seroincidence rate of 15.9 birds per 100 bird-months at risk (95% CI 11.9-19.8). ND seroreversion rate was 6.2 birds per 100 bird-months at risk (95% CI 3.6-8.9). Regarding risk factors for ND, temporal variations occurred, and ND was more likely to be present in the Sudanian agro-ecological zone than in the Sahelian zone, in chickens than in other species, in flocks with higher numbers of Guinea fowl, and in flocks that had access to a waterbody. Control efforts would benefit from further increasing the ND vaccination coverage of village poultry, although this was already quite high (54.9%) for an African country. Seroconversion seemed satisfactory in vaccinated poultry, since 90.0% (95% CI 87.6-92.4) of these had ND antibodies. Further research should investigate the apparent lack of an epidemiologic role of domestic ducks for AI in Mali (unlike in Southeast Asia) and the potential role of Guinea fowl as a reservoir for ND.

Serosurvey of Crimean-Congo Hemorrhagic Fever Virus in Cattle, Mali, West Africa.

AbstractCrimean-Congo hemorrhagic fever is a tick-borne disease caused by the arbovirus Crimean-Congo hemorrhagic fever virus (CCHFV, family Bunyaviridae, genus Nairovirus). CCHFV can cause a severe hemorrhagic fever with high-case fatality rates in humans. CCHFV has a wide geographic range and has been described in around 30 countries in the Middle East, Asia, Europe, and Africa including Mali and neighboring countries. To date, little is known about the prevalence rates of CCHFV in Mali. Here, using banked bovine serum samples from across the country, we describe the results of a seroepidemiological study for CCHFV aimed at identifying regions of circulation in Mali. In total, 1,074 serum samples were tested by a modified in-house CCHFV-IgG-enzyme-linked immunosorbent assay (ELISA) with confirmatory testing by commercial ELISA and immunofluorescence assay. Overall, 66% of samples tested were positive for CCHFV-specific IgG antibodies. Regional seroprevalence rates ranged from 15% to 95% and seemed to correlate with cattle density. Our results demonstrate that CCHFV prevalence is high in many regions in Mali and suggest that CCHFV surveillance should be established.

Dromedary camels in northern Mali have high seropositivity to MERS-CoV.

A high percentage (up to 90%) of dromedary camels in the Middle East as well as eastern and central Africa have antibodies to Middle East respiratory syndrome coronavirus (MERS-CoV). Here we report comparably high positivity of MERS-CoV antibodies in dromedary camels from northern Mali. This extends the range of MERS-CoV further west in Africa than reported to date and cautions that MERS-CoV should be considered in cases of severe respiratory disease in the region.

Molecular Characterization of Canine Rabies Virus, Mali, 2006-2013.

We genetically characterized 32 canine rabies viruses isolated in Mali during 2006-2013 and identified 3 subgroups that belonged to the Africa 2 lineage. We also detected subgroup F rabies virus. This information should be useful for development of mass vaccination campaigns for dogs and eventual large-scale control programs in this country.

Characteristics of commercial and traditional village poultry farming in Mali with a focus on practices influencing the risk of transmission of avian influenza and Newcastle disease.

We aimed at characterizing commercial and traditional village poultry farming in Mali, with a focus on practices influencing the risk of transmission of avian influenza and Newcastle disease. Surveys were conducted in 2009-2011 in a study area covering approximately 98% of the Malian poultry population. Among the 282 commercial farms investigated, of which 64 had not been known by the government authorities, 83% were located within a 50km radius from the capitals of the country and regions and 54% had low biosecurity standard. Among the 152 randomly selected village household flocks investigated, characteristics were overall similar to those in other African countries but some differences were notable including a large flock size (median 44 poultry), a low presence of ducks and geese (11% and 1.1% of flocks, respectively), vaccination against Newcastle disease being common (49% of flocks), a low proportion of households selling sick and dead birds (0.7% and 0%, respectively) and limited cohabitation between poultry and humans at night. Our recommendations to limit the risk of disease transmission include (1) for commercial farms, to introduce compulsory farm registration and accreditation, to increase technical proficiency and access to credit for farms with low biosecurity, and to support poultry producer associations; (2) for village poultry, to promote better quarantine and management of sick and dead birds. Such detailed knowledge of country-specific characteristics of poultry production systems is essential to be able to develop more efficient disease risk management policies.