Risk factors for infection with equine influenza virus in donkeys (Equus asinus) in Senegal

Abstract

In recent years, outbreaks of equine influenza are reported in several countries in the world particulary in Africa. This study is designed to assess the potential risk factors associated with equine influenza virus infection in donkeys in Senegal. The study consists in comparing, depending on the exposure to risk factors, a batch of donkeys infected with the equine influenza virus to another batch of donkeys not infected with the virus during the epizootic of March 2019 which affected the department of Foundiougne. The study reveals that the spread of the equine influenza virus in Foundiougne is associated with the lack of access to veterinary care and infected donkeys were exposed in a ratio of 2 times (95% CI: 1.38; 4.71) more than donkeys unharmed. The wandering of donkeys is also linked with the disease. The indicator reflecting the strength of the relationship, the Odds Ratio is 2.06 (95% CI: 1.10; 3.87). However, the results indicate that attendance at rural markets (Odds Ratio = 0.90; 95% CI: 0.44; 1.82), young age (Odds Ratio = 0.90; 95% CI: 0.52, 1.55) and female sex (Odds Ratio = 0.97; 95% CI: 0.57; 1, 66) do not appear to be related to the spread of the disease. At present, in Senegal, control focused on sensitizing and informing donkey owners on the sanitary management and rational use of donkeys is essential for their well-being.

Disease progression, pathologic, and virologic findings of an equine influenza outbreak in rescue donkeys

“…18 In this regard, it has been hypothesized that the heavy workload of donkeys (potentially leading to immunosuppression) combined with lack of preventative care might explain the higher susceptibility and mortality of donkeys reported in the literature. 4,18,25 Necropsy findings in the 3 donkey foals consisted of diffuse pulmonary consolidations with regions of bronchial and alveolar necrosis and mirrored previously reported necropsy findings in equids. 7 In horses, sporadic fatalities have been reported in foals, 7,8 but widespread disease in foals <6 months of age is uncommon and only has been reported during 1 disease outbreak.…”

“…Unfortunately, many donkey owners neglect to vaccinate their animals 5 . This neglect might be related to economic constraints, lack of access to vaccines, ignorance, vaccine hesitancy, and a misguided belief in a low susceptibility to infectious disease in donkeys 5,18,25 . Consequently, many donkeys (including foals from unvaccinated dams) remain at a substantial risk of infectious diseases of horses, especially if additional risk factors such a commingling, stress, and comorbidities are present.…”

“…In many countries of the world, donkeys are working equids and are used as a towing force in agriculture to transport people and goods, and for garbage collection. 18 In this regard, it has been hypothesized that the heavy workload of donkeys (potentially leading to immunosuppression) combined with lack of preventative care might explain the higher susceptibility and mortality of donkeys reported in the literature. 4,18,25 Necropsy findings in the 3 donkey foals consisted of diffuse pulmonary consolidations with regions of bronchial and alveolar necrosis and mirrored previously reported necropsy findings in equids.…”

“…Infections of donkeys with H3N8 EIV have been identified in numerous geographical regions and countries, including the United States, 9 Brazil, 10 Chile, 11 Europe, 12,13 China, 14‐17 Senegal, 18 Pakistan, 19 Turkey, 20 West and Central Africa, 4,21 Egypt, 22 and India 23 . In addition, the transmission of the highly pathogenic avian influenza H5N1 virus to donkeys in Egypt also has been reported 24 .…”

“…6 The disease incidence in young foals is generally lower, because of the presence of maternally-derived antibodies, 1,2 but foals that are born to unvaccinated mares are thought to have increased susceptibility to developing severe clinical disease. 7,8 Infections of donkeys with H3N8 EIV have been identified in numerous geographical regions and countries, including the United States, 9 Brazil, 10 Chile, 11 Europe, 12,13 China, [14][15][16][17] Senegal, 18 Pakistan, 19 Turkey, 20 West and Central Africa, 4,21 Egypt, 22 and India. 23 In addition, the transmission of the highly pathogenic avian influenza H5N1 virus to donkeys in Egypt also has been reported.…”