Molecular Diagnosis of Subclinical African Trypanosoma vivax Infection and Association with Physiological Indices and Serum Metabolites in Extensively Managed Goats in the Tropics

Abstract

Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend on animal reservoirs with subclinical parasitemia. We report molecular diagnosis of subclinical Trypanosoma vivax (T. vivax) infection using polymerase chain reaction (PCR) for the first time in Nigerian goats and associate parasite presence with gross physiological traits and serum metabolites in extensively managed Nigerian goats. PCR was used to amplify a 400 bp DNA fragment of the parasite genome in 205 goats across three geographical zones of the country. Results showed a high subclinical infection rate (SCIR) of 71.7% in the total goats examined. Overall SCIRs of 71%, 75.9% and 55.6% were recorded in West African Dwarf, Red Sokoto and Sahel goats respectively, while geographical SCIRs were 71.2% (Southwest), 75% (Northwest) and 70% (Northeast). T. vivax presence had significant (P < 0.05) effect on respiratory rate and is associated with higher creatinine levels in sera. Logistic regression analyses with Hosmer-Lemeshow goodness-of-fit showed that respiratory rate is the most important predictive trait for the presence of T. vivax infection (P < 0.05). Goats appear to be a viable reservoir for T. vivax infection of other livestock. Molecular diagnosis of subclinical trypanosomosis using PCR could be useful for large scale epidemiological studies, early diagnosis of subclinical infection and treatment of the disease in extensively managed tropical goats.

Comparative hematological analysis of Morada Nova and Santa Inês ewes in all reproductive stages

“…Previous studies of red cells during pregnancy have produced conflicting results, although most have been conducted with goats and cattle, and have demonstrated a decreased number of red blood cells at birth (Earley et al 2013, Sanni et al 2013. However, other studies have demonstrated an increase in the number of red blood cells or hemoglobin levels, and some studies have been unable to verify differences in the erythrocyte counts, packed cell volumes and hemoglobin levels in samples taken during pregnancy compared to those taken immediately after delivery.…”

Parameters Influencing Haematological, Serum and Bio-Chemical References in Livestock Animals under Different Management Systems

“…In mammals, respiration is the direct expulsion of carbon dioxide from tissues of the body and elimination of moisture from respiratory tract to help prevent hyperthermia under high ambient temperatures, which is a major adaptive feature of domestic livestock in the hot tropical Africa. The rate of respiration was found to be largely affected by pathogenic T. vivax [35]. The reduction in the respiratory rate of goats infected with pathogenic T. vivax indicates that the infected animals may be more stressed than their non-infected counterpart.…”

“…The reduction in the respiratory rate of goats infected with pathogenic T. vivax indicates that the infected animals may be more stressed than their non-infected counterpart. This is an indication that pathogenic T. vivax could be referred to as stressor in goats and the measurement of respiratory rate is an indication of the physiological alterations of stressed and infected animals as caused by T. vivax [35]. Thermal stressor as a form of environmental heat stress negatively influenced livestock physiological activities especially when an animal is having difficulty in dissipating excess heat load to its environment which subsequently frustrate overall performance e.g.…”

Field and experimental symptomless infections support wandering donkeys as healthy carriers of Trypanosoma vivax in the Brazilian Semiarid, a region of outbreaks of high mortality in cattle and sheep

“…The successive outbreak reports from distantly separated regions suggested that T. vivax is presently widespread in former non-endemic regions of Brazilian Semiarid where outbreaks have been reported in dairy cattle and sheep. Although serological surveys suggested that T. vivax was not disseminated in cattle herds in areas where previous outbreaks were controlled by the treatment of all symptomatic animals [ 8 , 9 ], the answer to this question requires extensive surveys using sensitive diagnostic methods in healthy goats, horses and donkeys, which are carriers of T. vivax in Africa [ 10 – 12 ].…”