About factors that determine trypanotolerance and prospects for increasing resistance against trypanosomosis

The current threat of African trypanosomosis on sustainable livestock production and food security coupled with failure of tse-tse fly control, chemotherapy and chemoprophylaxis to control the present resurgence of the disease has increased the imperative need for increasing trypanotolerance in livestock. The innate ability of trypanosome infected animals to control anaemia and development of parasitaemia are some of the indicators of trypanotolerance. In the last few years, research had aimed at identifying the various factors involved in trypanotolerance. Even though haematopoietic and antitrypanosome serum lytic factors have been associated with ability to control the development of anaemia and parasite respectively, trypanotolerance is a genetically defined complex mechanism involving factors which are not yet well known. Recent molecular based research using mice and cattle identified genomic regions controlling trypanotolerance in animals. Although these biotechnologies have not been able to identify the complete  pool of genes involved in trypanotolerance, they have raised the hope of producing synthetic breeds of animals with higher trypanotolerance level, and enhancing the tolerance of susceptible breeds

Hematological derangement patterns in Nigerian dogs infected with Trypanosoma brucei: A simple prototype for assessing tolerance to trypanosome infections in animals

The haematology of Nigerian local puppies experimentally infected with the Federe strain of Trypanosoma brucei was studied in a total of six 9-weeks old puppies born to two local bitches. Four were randomly selected and inoculated with about 0.8 x 106 of T .brucei subcutaneously and the remaining two served as the uninfected control. The parasitaemia was monitored daily using wet mount microscopy. The packed cell volume (PCV), red blood cell (RBC) counts, total and differential white blood cell (WBC) counts and rates of both red blood cell and white blood cell loss per day and per parasitaemia log equivalent value(LEV) were monitored twice in a week . Parasitaemia was detected in the infected group four days after infection which was followed by an acute disease course, though with low fatality rate in the dogs. The anemia was characterized by a fluctuating PCV decrease from the pre-infection value of 29.5±4.5% and 15.3±3.3% at two weeks after infection when one of the dogs died. There was a mild decrease in the overall erythrocyte values which was attributable to trypanotolerance in the local breed of dogs. The post infection hematological derangement pattern was characterized by an overall post-infection RBC count drop of 1.92+0.23(x 1012/μ) (39.0%), mean daily drop of 0.07+0.05 (x 1012/μ) and an overall drop per LEV of 0.69(x 1012/μ). The overall mean postinfection total WBC count drop was 0.61±0.15(x109/μ)(43.6%) with a mean daily drop of 0.02±0.14(x109/μ), and an overall drop per LEV of 0.22±0.44(x109/μ). There was an overall higher post infection leukocyte drop compared to erythrocyte. The result poses fundamental research questions on the likelihood of differential surface sialic acid contents of erythrocytes and leukocytes and the possible roles of trypanosome sialidase in creating this difference as well as enhancing pathogenesis of leucopenia in the dogs . It was concluded that the patterns of hematological derangements demonstrated as erythrocyte and leukocyte drop (loss) rates and drop per parasitaemia Log Equivalent Values could serve as a prototype for comparing susceptibility to animal and human T. brucei infections and, other trypanosome species.Keywords: Federe, Trypanosoma brucei, haematology, derangement, pattern

Serum biochemical parameters and cytokine profiles associated with natural African trypanosome infections in cattle.

BACKGROUND: Animal African trypanosomiasis (AAT) greatly affects livestock production in sub-Saharan Africa. In Ghana prevalence of AAT is estimated to range between 5 and 50%. Studies have reported serum biochemical aberrations and variability in cytokine profiles in animals during infection. However, information regarding the biochemical parameters and cytokine profiles associated with natural infections are limited. This study was therefore aimed at investigating changes in the levels of serum biochemical parameters and inflammatory cytokines during a natural infection. METHODS: Nested internal transcribed spacer (ITS)-based PCR and sequencing were used to characterise trypanosome infection in cattle at two areas in Ghana (Adidome and Accra) of different endemicities. The cattle were sampled at four to five-week intervals over a period of six months. Levels of serum biochemical parameters, including creatinine, cholesterol, alkaline phosphatase (ALP), alanine aminotransferase (ALT), total bilirubin and total protein and cytokines (interleukin 10, interleukin 4, interleukin 12, interferon gamma and tumor necrosis factor alpha) were measured in serum samples and then compared between infected cattle and uninfected controls. RESULTS: The predominant trypanosome species detected in Accra (non-endemic) and Adidome (endemic) were Trypanosoma theileri and Trypanosoma vivax, respectively. Serum biochemical parameters were similar between infected and uninfected cattle in Accra. Infected cattle at Adidome however, had significantly higher levels of ALP, creatinine, total protein and total bilirubin (P < 0.05) and significantly lower levels of cholesterol (P < 0.05) at specific time points. At basal levels and during infection, significantly higher pro-inflammatory to anti-inflammatory (Th1/Th2) cytokine ratios were observed in cattle at Adidome compared to Accra (P < 0.05), indicating a shift towards Th1 immune response in Adidome. Levels of IL-10 were, however, significantly elevated in infected cattle in Accra (P < 0.05), suggesting high anti-inflammatory cytokine response in Accra. CONCLUSION: These results suggests that cattle in an endemic area repeatedly infected with trypanosomes of different species or different antigenic types demonstrate high pro-inflammatory (Th1) immune response and biochemical alterations whereas cattle in a non-endemic area with predominantly chronic T. theileri infections demonstrate high anti-inflammatory response and no biochemical alterations

The Prevalence Of Trypanosome Infection In Trade Cattle, Goats And Sheep Slaughtered At The Kaduna Abattoir

The prevalence of trypanosome infection in trade cattle, goats and sheep was investigated in slaughtered animals at the Kaduna Abattoir. Wet, thin, thick films, animal inoculation, haematocrit centrifugation technique and buffy coat methods were used to detect rypanosomes in the jugular blood of the animals. The packed cell volume (PCV) was also determined. A total of 300 cattle, 300 goats and 300 sheep were examined within five months (September, 1998 – January, 1999) and the prevalence rates in cattle, goats and sheep were found to be 5.00%, 4.67% and 3.33% respectively. Mean PCV of infected cattle was 20.33% against uninfected cattle 35.08%. In goats, the PCV was 20.29%, uninfected goats 31.56%; while that of sheep was 19.40% and uninfected 32.85%. Trypanosoma vivax infection accounted for 60%, T. brucei 26.67% and T. congolense 13.33% in cattle. In goats, T. vivax infection accounted for 71.43%, T. brucei 21.43% and T. congolense 7.14%. Also T. vivax infection accounted for 70%, T. brucei 30% and T. congolense 0% in sheep. Sex did not significantly (P>0.05) affect infection rates. Although the prevalence rate of trypanosomiasis in cattle, goats and sheep appeared low compared with the previous works, natural trypanosomiasis remains economically importance in cattle, goats and sheep in Nigeria.African Journal of Clinical and Experimental Microbiology Vol. 10 (1) 2009: pp. 15-2

Effect of trypanosoma congolense and Trypanosoma brucei mixed infection on the pattern of haematological changes in murine trypanosmosis

The effect of Trypanosoma congolense and T. brucei mixed infection on the pattern of haematological changes was demonstrated in a rat model. At the end of 21 days post infection (PI), anaemia which was characterised by drop in the packed cell volume (PCV), was found to be significantly (

Observations on the tolerance of young dogs (puppies) to infection with Trypanosoma congolense

Studies were undertaken to assess the susceptibility of young local dogs to infection with Trypanosoma congolensei. Six puppies (7 weeks old) were used for the study. Although the puppies became parasitaemic 6 to 7 days post infection, they were tolerant to infection as the parasitaemia remained low through out the first seven weeks of the eight week observation period. The packed cell volume (PCV) also only dropped slightly during the last four weeks attaining the value of 25.6 + 3.8 (p>0.05) by the eighth week while the mean body weight continued to increase. Similarly, the mean daily body temperature did not differ significantly from those of un-infected control. The significance of trypanotolerance in Nigerian local dogs is discussed. Key Words: local puppies, low parasitaemia, packed cell volume, Trypanosoma congolense, trypanotolerance, Nigerian Afr. J. Clin. Exper. Microbiol. Vol.6(1) 2005: 28-3

Prevalence of trypanosomosis in trade cattle at slaughter in Kaduna, Nigeria

No Abstract. The Nigerian Journal of Parasitology Vol. 23(1) 2002: 107-11