Assessing the performance of a Fasciola gigantica serum antibody ELISA to estimate prevalence in cattle in Cameroon

Abstract

BackgroundCattle rearing in Cameroon is both economically and culturally important, however parasitic diseases detrimentally impact cattle productivity. In sub-Saharan Africa bovine fasciolosis is generally attributed to F. gigantica, although understanding of Fasciola species present and local epidemiology in individual countries is patchy. Partly limited by the lack of representative surveys and understanding of diagnostic test perfromance in local cattle populations. The aims of this paper were to determine the Fasciola species infecting cattle, develop a species specific serum antibody ELISA, assess the performance of the ELISA and use it to assess the prevalence of F. gigantica exposure in two important cattle-rearing areas of Cameroon.ResultsA random sample of Fasciola parasites were collected and were all identified as F. gigantica (100%, CI:94.0–100%, n = 60) using RAPD-PCR analysis. A F. gigantica antibody ELISA was developed and initially a diagnostic cut-off was determined using a sample of known positive and negative cattle. The initial cut-off was used as starting point to estimate an optimal cut-off to estimate the best combination of sensitivity and specificity. This was achieved through sampling a naturally infected population with known infection status (cattle slaughtered at Bamenda abattoir, North West Region (n = 1112) and Ngaoundere abattoir, Vina Division, Adamawa Region (n = 776) in Cameroon). These cattle were tested and results analysed using a Bayesian non-gold standard method. The optimal cut-off was 23.5, which gave a sensitivity of 65.3% and a specificity of 65.2%. The prevalence of exposure to F. gigantica was higher in cattle in Ngaoundere (56.4% CI: 50.2–60.0%) than Bamenda (0.6% CI: 0.0–1.4%).ConclusionFasciola gigantica was identified as the predominant Fasciola species in Cameroon. Although the sensitivity and specificity F. gigantica antibody ELISA requires improvement, the test has shown to be a potentially useful tool in epidemiological studies. Highlighting the need for better understanding of the impact of F. gigantica infections on cattle production in Cameroon to improve cattle production in the pastoral systems of Central-West Africa. This paper also highlights that non-gold standard latent class methods are useful for assessing diagnostic test performance in naturally-infected animal populations in resource limited settings.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1762-z) contains supplementary material, which is available to authorized users.

A socio-economic study of Fasciola infections in cattle and sheep at the Etoudi slaughterhouse, Yaoundé, Cameroon

“…However, Bafia at 467 m asl is not so high; therefore, it is unclear why no infections were found. A study that was carried out in 2012/2013 suggested a prevalence of 0.4% in cattle at the Bamenda abattoir, around 80 km from Bafoussam, which may suggest that there is a low prevalence within this area (Kelly et al ., 2019). Further work should be undertaken to investigate fascioliasis in these areas and to examine if the snail intermediate host is present.…”

Fascioliasis: A Foodborne Disease of Veterinary and Zoonotic Importance

“…In sub-Saharan Africa (SSA), fascioliasis has been reported in West Africa [12,31], East Africa [32], and South African countries [33,34]. However, it has also been reported in Egypt (outside SSA), North Africa [35,36].…”

“…Fascioliasis due to F. g igantica is predominantly endemic in the lower altitudes of tropical and subtropical parts of the world. Consequently, more cases of the disease are reported in larger part of sub-Saharan Africa (SSA) where suitable snail intermediate hosts naturally inhabit [10][11][12].…”

Fasciolosis: A Major Global Foodborne Zoonosis

“…As a result, more disease cases are being recorded in a more significant portion of Sub-Saharan Africa (SSA), where suitable snail intermediate hosts occur naturally (Kelly et al 2019). Due to the high prevalence of Fasciolid infection in humans, this disease has been underestimated.…”