Microscopy Underestimates the Prevalence of Trypanosomes’ Infection in Asymptomatic Cattle and Sheep in a Lowland Area within the Kenyan Rift Valley

作     者：Emmily C. Ngetich Ng’wena Gideon Magak Ngeiywa Moses 

作者机构：Department of Biological and Biomedical Sciences Laikipia University Nyahururu Kenya Department of Biological Sciences School of Science University of Eldoret Eldoret Kenya Department of Medical Physiology School of Medicine Maseno University Maseno Kenya 

出 版 物：《Open Journal of Veterinary Medicine》 (兽医学（英文）)

年 卷 期：2019年第9卷第9期

页      面：136-145页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

主　　题：Kerio Valley Microscopy Polymerase Chain Reaction Trypanosomosis 

摘      要：Animal trypanosomosis continues to impede animal production in sub-Saharan Africa mostly in locations where tsetse flies are endemic. This has ended up devastating many livelihoods where majority of the people depend on livestock farming as source of food and income generation. The true picture on prevalence and identity of trypanosome species is scanty or unknown in most areas where tsetse flies are present. This study sought to investigate the prevalence of trypanosomes’ infection in cattle and sheep using microscopy and polymerase chain reaction (PCR) methods. The use of PCR for detection and identification of trypanosomes has increased sensitivity of diagnostic method compared to conventional microscopy. Ninety asymptomatic free range grazed animals including 72 cattle and 18 sheep randomly sampled from farmers in Kerio Valley of Elgeyo-Marakwet County, Kenya were used in the present study. Blood samples (5 ml) obtained from each of the animals were used for trypanosomes’ detection by microscopy and PCR assay methods. Microscopy results showed that only 2 cattle (2.8%) were positive for trypanosomosis infection. The microscopy results for the sheep showed zero prevalence. On the other hand, PCR results reported 26 trypanosomosis positive cattle (36.1%) and 3 (16.7%) trypanosomosis positive sheep. The PCR method was further used for trypanosomes’ species identification and the results showed that the 26 infected cattle were positive for T. congolense (12) and T. brucei (14) while the three sheep were all positive for T. brucei. The findings of the present study show that microscopy underestimates trypanosomosis detection and therefore cannot be relied upon as a tool for diagnosis. Besides, the method is weak in reporting species differentiation in a case where the morphological differences have only minor details or where the species are very close morphologically. This study recommends routine use of molecular biology-based technique for trypanosomosis detection