Molecular survey of pathogenic trypanosomes in naturally infected Nigerian cattle Michael I. Takeet a,b,c,⇑ , Benjamin O. Fagbemi b , Marcos De Donato a,d , Abdulmojeed Yakubu a,e , Hectorina E. Rodulfo d , Sunday O. Peters a,f , Matthew Wheto f , Ikhide G. Imumorin a,⇑ a Dept. of Animal Science, Cornell University, Ithaca, NY 14853, USA b Dept. of Veterinary Microbiology and Parasitology, University of Ibadan, Ibadan, Nigeria c Dept. of Veterinary Microbiology and Parasitology, University of Agriculture, Abeokuta, Nigeria d Dept. of Biomedicine, Universidad de Oriente, Cumana, Venezuela e Dept. of Animal Science, Nasarawa State University, Lafia, Nigeria f Dept. of Animal Science, Berry College, Mount Berry, GA 30149, USA article info Article history: Received 18 June 2012 Accepted 21 October 2012 Keywords: Cattle Molecular diagnostics Nigeria PCR Trypanosomes abstract Microscopy and polymerase chain reaction (PCR) were used to survey pathogenic trypanosome infection in naturally infected Nigerian cattle. In 411 animals sampled, microscopy detected 15.1% positive infec- tion of at least one of Trypanosoma brucei, Trypanosoma congolense or Trypanosoma vivax, while PCR detected 63.7% positive infections of at least one of those species and Trypanosoma evansi. PCR detected 4.4%, 48.7%, 26.0% and 0.5% respectively of T. brucei, T. congolense, T. vivax and T. evansi infections. All of the T. congolense detected were savannah-type, except for two forest-type infections. Prevalence of mixed infections was 13.9%, being primarily co-infection by T. congolense and T. vivax while prevalence of mixed infections by T. evansi, T. vivax and T. congolense was 1.5%. Microscopy showed poor sensitivity but spec- ificity greater than 94%. Infection rates were much higher in Southern than in Northern Nigeria. Infections were lowest in N’dama compared to Muturu, Sokoto Gudali and White Fulani breeds. Animals with T. vivax monoinfection and mixed infections showed significantly lower packed cell volume (PCV) values. Those infected with any Trypanosoma species with <200 parasites/ll showed higher PCV values than those infected with >200 parasites/ll. The new finding of savannah- and forest- type T. congolense in Nigeria and the relatively high abundance of mixed infections are of significant clinical relevance. This study also suggests that T. congolense is the most prevalent species in Nigeria. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Trypanosomosis is a complex infectious disease of animals caused by a range of extra-erythrocytic protozoan parasites of the genus Trypanosoma, responsible for production losses, morbid- ity and sometime mortality in infected herds (Abenga et al., 2002). The clinical signs of trypanosomosis depend on the species and strain of the infecting trypanosome, breed of the animal involved (Anene et al., 1991a,b; Matioli et al., 1998) and the prevalence of vectors (Leak et al., 1990; Onyiah, 1997; Merkuria and Gadissa, 2011). Clinical signs include anemia, intermittent fever, parasita- emia, lymphadenopathy, jaundice, progressive emaciation, loss of production, weakness and death, if left untreated (Akinwale et al., 1999; Merkuria and Gadissa, 2011). While Muturu and N’dama are considered trypanotolerant breeds because they strive well under the pressure of trypanosome infections, they act as res- ervoirs of the infection for other animals (Moloo et al., 1992). In Nigeria, diagnosis of bovine trypanosomosis largely depends on parasitological and immunological methods. Parasitological techniques have significant limitations exemplified by inability to differentiate between Trypanosoma brucei and Trypanosoma evansi except through the molecular composition of their kinetoplast DNA (kDNA) (Artama et al., 1992; Feng-Jun et al., 2007). Within species, parasitological methods can identify Trypanosoma congo- lense but not sub groups of the parasite. Hence, this technique lacks the sensitivity and the precision required for the purpose of ade- quate therapeutic and prophylactic control measures, exacerbated by a high proportion of false negative results. Immunological tech- niques (i.e. enzyme linked immunosorbent assays, card agglutina- tion and fluorescent antibody tests) on the other hand are good for large scale epidemiological studies (Greiner et al., 1997) but not sensitive enough to detect and differentiate between current and previous infections, also leading to false positive results (Desquesnes and Tresse, 1996). Molecular technique such as polymerase chain 0034-5288/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.rvsc.2012.10.018 ⇑ Corresponding authors. Addresses: Dept. of Veterinary Microbiology and Parasitology, Federal University of Agriculture, Abeokuta, Nigeria. Tel.: +234 (803) 7872682 (M.I. Takeet), Dept. of Animal Science, 267 Morrison Hall, Cornell University, Ithaca, NY 14853, USA. Tel.: +1 (607) 255 2850; fax: +1 (607) 255 9829 (I.G. Imumorin). E-mail addresses: takeetm@yahoo.com (M.I. Takeet), igi2@cornell.edu (I.G. Imumorin). Research in Veterinary Science 94 (2013) 555–561 Contents lists available at SciVerse ScienceDirect Research in Veterinary Science journal homepage: www.elsevier.com/locate/rvsc