Since 2006, multiple outbreaks of avian influenza (AI) have been reported in Nigeria involving different subtypes. Surveillance and molecular epidemiology have revealed the vital role of live bird markets (LBMs) in the dissemination of AI virus to commercial poultry farms. To better understand the ecology and epidemiology of AI in Nigeria, we performed whole-genome sequencing of nineteen H9N2 viruses recovered, from apparently healthy poultry species, during active surveillance conducted in nine LBMs across Nigeria in 2019. Analyses of the HA gene segment of these viruses showed that the H9N2 strains belong to the G1 lineage, which has zoonotic potential, and are clustered with contemporary H9N2 identified in Africa between 2016 and 2020. We observed two distinct clusters of H9N2 viruses in Nigeria, suggesting different introductions into the country. In view of the zoonotic potential of H9N2 and the co-circulation of multiple subtypes of AI virus in Nigeria, continuous monitoring of the LBMs across the country and molecular characterization of AIVs identified is advocated to mitigate economic losses and public health threats.
Among recurrent sanitary emergencies able to spread rapidly worldwide, avian influenza is one of the main constraints for animal health and food security. In West Africa, Nigeria has been experiencing repeated outbreaks of different strains of avian influenza virus (AIV) since 2006 and is also recognized as a hot spot in the region for the introduction of emerging strains by migratory wild birds. Here, we generated complete genomes of 20 highly pathogenic avian influenza (HPAI) H5N8 viruses collected during active surveillance in Nigerian live bird markets (LBM) and from outbreaks reported in the country between 2016 and 2019. Phylogenetic analysis reveals that the Nigerian viruses cluster into four separate genetic groups within HPAI H5 clade 2.3.4.4b. The first group includes 2016–2017 Nigerian viruses with high genetic similarity to H5N8 viruses detected in Central African countries, while the second includes Nigerian viruses collected both in LBM and poultry farms (2018–2019), as well as in Cameroon, Egypt and Siberia. A natural reassortant strain identified in 2019 represents the third group: H5N8 viruses with the same gene constellation were identified in 2018 in South Africa. Finally, the fourth introduction represents the first detection in the African continent of the H5N6 subtype, which is related to European viruses. Bayesian phylogeographic analyses confirmed that the four introductions originated from different sources and provide evidence of the virus spread within Nigeria, as well as diffusion beyond its borders. The multiple epidemiological links between Nigeria, Central and Southern African countries highlight the need for harmonized and coordinated surveillance system to control AIV impact. Improved surveillance at the Wetlands, LBMs and early warning of outbreaks are crucial for prevention and control of AIV, which can be potentially zoonotic and be a threat to human health.
In 2021, amidst the COVID-19 pandemic and global food insecurity, the Nigerian poultry sector was exposed to the highly pathogenic avian influenza (HPAI) virus and its economic challenges. Between 2021 and 2022, HPAI caused 467 outbreaks reported in 31 of the 37 administrative regions in Nigeria. In this study, we characterized the genomes of 97 influenza A viruses of the subtypes H5N1, H5N2, and H5N8, which were identified in different agro-ecological zones and farms during the 2021–2022 epidemic. The phylogenetic analysis of the HA genes showed a widespread distribution of the H5Nx clade 2.3.4.4b and similarity with the HPAI H5Nx viruses that have been detected in Europe since late 2020. The topology of the phylogenetic trees indicated the occurrence of several independent introductions of the virus into the country, followed by a regional evolution of the virus that was most probably linked to its persistent circulation in West African territories. Additional evidence of the evolutionary potential of the HPAI viruses circulating in this region is the identification in this study of a putative H5N1/H9N2 reassortant virus in a mixed-species commercial poultry farm. Our data confirm Nigeria as a crucial hotspot for HPAI virus introduction from the Eurasian territories and reveal a dynamic pattern of avian influenza virus evolution within the Nigerian poultry population.
Influenza A virus presents a significant public health burden worldwide, with the 1918 Spanish flu pandemic being the most dramatic example. Swine influenza viruses can be transmitted to humans through occupational exposures and in live pig markets. Novel variants can emerge in pigs because they can be infected by human, avian and swine strains. This study was carried out to determine the seroprevalence and serotypes of swine influenza in pigs from a major slaughter slab in southern Kaduna. Using competitive ELISA and haemagglutination-inhibition (HI) assays, 305 swine sera were analysed. The result showed an overall seroprevalence of 28.20% (n=86), with H3N2 7.87% (n=24) emerging as the most dominant subtype in circulation. Concurrent antibody detection of H1N1 in 5.26% (n=16) was also detected in boar 2.62% (n=8) and sows 2.62% (n=8). This study revealed swine Influenza H1N1 and H3N2 serotypes are in circulation in pigs in Kaduna State, and that reassortment in the instance of co-infection of swine host is possible.
The control of highly pathogenic avian influenza (HPAI) in Nigeria from inception is predicated on effective biosecurity by stamping out policy but outbreaks of the disease continued to re-occur with altered clinico-pathologic manifestations. This study undertook the qualitative assessment of the clinico-pathological features of HPAI H5N1 during the 2021/2022 outbreaks in commercial poultry and peri-domestic birds in northern Nigeria. A total of 22 commercial poultry farms with 53,932 laying chickens and 3 households with 120 backyard broiler chickens, 18 indigenous chickens, 10 peafowls and 9 geese were investigated for HPAI. The clinico-pathologic manifestations observed in commercial poultry were subtle compared to previous presentations of the disease except in the peafowls, geese, broilers and indigenous chickens. The interspecies mortality rates significantly varied from 1.6% to 19.6% for laying chickens and 33.3% to 100% for broilers, indigenous chickens, geese and peafowls. Based on the history of sudden and high mortality, clinical signs and post mortem lesions observed, three diseases; HPAI, very virulent Newcastle disease and fowl cholera were drawn out as differential diagnoses. However, a tentative diagnosis of HPAI was made and samples were sent to the National Veterinary Research Institute, Vom, Plateau State, Nigeria for confirmatory diagnosis. Results of the laboratory tests conducted on the samples using one step flu A screening and duplex real time RT-PCR,
Animals with cloven hooves are susceptible to highly contagious foot and mouth disease (FMD). FMD epidemics have affected several underdeveloped countries, including Nigeria. The migration of pastoralist animals has been linked to FMD transmission in Nigeria, and surveillance is essential for assessing the threat and impact of FMD, as well as the emergence of PCP-FMD. Here, we report the sero-surveillance of FMD in cattle in four states in Nigeria in 2019. Sera collected from four states (Anambra, Enugu, Imo, and Katsina) were tested for antibodies against FMD non-structural protein (NSP), with an overall prevalence of 45%. Significantly higher seroprevalence was recorded in Imo (63%), followed by Kastina (56%), Anambra (29%), and Enugu (6%). An overall serotype-specific prevalence of 81%, 35 %, 50 %, and 35% was recorded for serotypes O, A, 50% for SAT 2, and SAT 1, respectively. Furthermore, circulating antibodies against four serotypes of FMDV were found in 16% of sera samples, 20% had antibodies against three circulating serotypes, 33% had antibodies against two serotypes, and 25% showed exposure to only one serotype, indicating exposure to multiple FMD serotypes. These findings demonstrate the presence of FMDV antibodies in cattle across all surveyed states, which may be related to the presence of multiple FMDV serotypes (O, A, SAT1and SAT2) and concurrent co-infection in these states. Therefore, there is a need for the continuous surveillance of FMD in Nigeria. This will help ascertain the burden of the disease and enable the implementation of necessary control measures to stop its potential transmission and further spread. This sero-surveillance data expands our understanding of the FMD situation in Nigeria and is crucial for determining the country’s FMD risk in order to advance the PCP-FMD.
Covid-19 pandemic has hit many countries and put the majority of the public health system to test globally. Mandatory use of facemask was among policies set by the government to contain the spread of the novel disease. But citizens’ attitudes and compliance with these policies are important in controlling the pandemic. We assessed gender-based compliance to Covid-19 protocol (use of face mask) in Jos South, Plateau State, Nigeria.
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