High prevalence of Toxoplasma gondii in Nigerian wild rats by molecular detection.

Toxoplasmosis has been reported in Nigeria using several diagnostic tools with high prevalence in humans and some food animals. Rodents have been recognised as vital intermediate hosts of Toxoplasma gondii. However, there is paucity of information on the occurrence of T. gondii in wild rats found in Nigeria. This study aimed at molecular detection of T. gondii in Zyzomys pedunculatus and to evaluate its involvement in the epidemiology of toxoplasmosis in Nigeria. A total of 84 rats were sampled across three states of the North Central Nigeria, and DNA was extracted from the brain, lungs, kidney and intestine of the rats for the detection of T. gondii DNA by nested PCR to amplify the multicopy B1 gene. Sixty-four of the 84 samples (76.2%) were positive for T. gondii out of which 5 samples were sequenced and had an identity score of between 97.73% and 99.35% with the reference B1 gene of T. gondii in GenBank. This study suggests Nigerian wild rats may be an important intermediate hosts of T. gondii and may play a role in the epidemiology and maintenance of T. gondii circulation in Nigeria.

Immunohistochemical detection and pathology of toxoplasmosis in Nigerian wild rats.

Toxoplasmosis is a zoonotic disease of economic importance found worldwide, and it is caused by Toxoplasma gondii, which affects a wide range of hosts. High prevalence of toxoplasmosis has been reported in rodents, and they are considered very important in the circulation and maintenance of the disease. However, epidemiologic studies of the disease in rodents are generally scarce in the Tropics. This study utilized the immunohistochemical (IHC) technique to detect Toxoplasma gondii in wild rats sampled from across the North Central Nigeria. The brain, intestine, diaphragm, lungs and kidney tissue samples from 227 wild rats (Zyzomys pedunculatus) were routinely processed for histopathology, out of which 86 were further selected for IHC detection of T. gondii antigens using the streptavidin-peroxidase method. The histologic lesions observed were mild to moderate in severity, including meningitis, focal gliosis, neuronal degeneration and necrosis, villous atrophy and denudation, enteritis, diaphragmatic myositis, broncho-interstitial pneumonia and interstitial nephritis. Toxoplasma gondii was detected in 82.6% of the selected samples showing various degrees of immunoreaction intensity. We conclude that IHC is a useful tool in the detection of T. gondii in wild rats, and lungs and kidney may be the organ of choice for the detection of T. gondii.

Molecular occurrence of trypanosomes, erythrocyte and serum sialic acid concentrations of Muturu and Bunaji cattle in Benue State, Nigeria.

One hundred each, of Muturu and Bunaji cattle were screened, using polymerase chain reaction (PCR), for trypanosomes in Makurdi and Gboko Local Government Areas of Benue State, Nigeria. Erythrocyte surface sialic acid (ESSA) and free serum sialic acid (FSSA) concentrations were determined and compared in both breeds with the aim of providing baseline data for research and diagnostic purposes. Five per cent (5%) and 23% of the Muturu and Bunaji cattle, respectively, were positive for trypanosomes. The result at p=0.005 was significantly different, with p value of 0.0002 and odd ratio of 0.1762. The Trypanosoma species circulating in Benue State, as detected in the two breeds of cattle, were Trypanosoma congolense, T. vivax, T. brucei and T. evansi. This study, therefore, reports for the first time a natural infection of cattle with T. evansi and the use of a novel PCR in the diagnosis of trypanosome infections in cattle in Benue State, Nigeria. The determination of the ESSA and FSSA concentrations in Muturu cattle in Nigeria is also reported for the first time. The Muturu cattle have a significantly higher ESSA than the Bunaji cattle, this may be responsible for their relative trypanotolerance.