Mechanisms controlling anaemia in Trypanosoma congolense infected mice.

Trypanosoma congolense are extracellular protozoan parasites of the blood stream of artiodactyls and are one of the main constraints on cattle production in Africa. In cattle, anaemia is the key feature of disease and persists after parasitaemia has declined to low or undetectable levels, but treatment to clear the parasites usually resolves the anaemia. The progress of anaemia after Trypanosoma congolense infection was followed in three mouse strains. Anaemia developed rapidly in all three strains until the peak of the first wave of parasitaemia. This was followed by a second phase, characterized by slower progress to severe anaemia in C57BL/6, by slow recovery in surviving A/J and a rapid recovery in BALB/c. There was no association between parasitaemia and severity of anaemia. Furthermore, functional T lymphocytes are not required for the induction of anaemia, since suppression of T cell activity with Cyclosporin A had neither an effect on the course of infection nor on anaemia. Expression of genes involved in erythropoiesis and iron metabolism was followed in spleen, liver and kidney tissues in the three strains of mice using microarrays. There was no evidence for a response to erythropoietin, consistent with anaemia of chronic disease, which is erythropoietin insensitive. However, the expression of transcription factors and genes involved in erythropoiesis and haemolysis did correlate with the expression of the inflammatory cytokines Il6 and Ifng. The innate immune response appears to be the major contributor to the inflammation associated with anaemia since suppression of T cells with CsA had no observable effect. Several transcription factors regulating haematopoiesis, Tal1, Gata1, Zfpm1 and Klf1 were expressed at consistently lower levels in C57BL/6 mice suggesting that these mice have a lower haematopoietic capacity and therefore less ability to recover from haemolysis induced anaemia after infection

Prevalence of Besnoitia besnoiti antibodies as related to skin lesions among indigenous and exotic cattle in northern Nigeria

A total of 400 cattle which comprised of 6 indigenous and 1 exotic breeds were examined for gross skin lesions in northern Nigeria. It was observed that 126 (31.5%) of the cattle had various gross skin lesions. The frequency of these skin lesions was highest (34.3%) among the White Fulani and lowest (2.8%) among the Friesian breed of cattle. Indirect immunofluorescence antibody technique (IFAT) used to analyse 64 milk and 336 sera samples for antibodies against Besnoitia besnoiti revealed 321 (80.3%) of the cattle positive to the test. The Association of antibodies against the parasite was high and varied (x2 = 0.6, p > 0.5) from 75.45% to 88.37% among the breeds. Cattle with apparently normal skin also higher (86.67%) prevalence of the antibodies, compared to 70.0% observed among those with gross skin lesions. It was concluded that breed and presence of skin lesions may not influence the seroprevalence of Bovine besnoitiosis in northern Nigeria.Keywords: Exotic breeds, Skin lesions, besnoitia besnoiti, immunofluorescence antibody technique, Friesian breedNigerian Journal of Parasitology, Vol. 32 [1] March 2011, pp. 31-3

Sialyltransferase activity probably counteracts that of sialidase as one of the possible mechanisms of natural recovery or stabilization of erythrocyte mass in trypanosome-infected animals - A perspective

Attempts to unravel the mechanisms of development of anaemia in trypanosome-infected animals yielded varying reports with those that implicate trypanosomal sialidase (SD) being among those thatenjoy prominence. Significant cleavage of sialic acid (SA) on erythrocyte membranes and terminal positions of erythropoietin (Epo) by SD, which is released during trypanosome infection of animals,results in their rapid clearance and destruction by cells of the mononuclear phagocytic system and in addition, in the case of Epo, decreased biologic activity of the hormone with consequent development of anaemia. Observations on free serum and erythrocyte surface SA profiles of trypanosome-infected animals suggest possible involvement of sialyltransferase (ST) in recovery or stabilization of red blood cell mass, which seems to be a probable explanation as to why some trypanosome-infected animals either recover from the anaemia or run a chronic infection with very low but stable erythrocyte mass.The speculated roles of ST open up a new and, probably, promising area of research; especially, if identification of mechanisms of natural resistance to trypanosome infection is of prime consideration inthis contemporary period of research in molecular medicine

Transhumance pastoralism as risk factor in the trypanosome infections in cattle

La transhumance pastorale en tant que facteur de risque d’infections à trypanosome chez le bétail a fait l’objet d’une étude en juin 2004, au sein des troupeaux sédentaires (résidents) et semi-sédentaires (de retour de transhumance), dans la l’aire de pâture de la réserve de Kachia, Etat de Kaduna, Nigeria. Le sang a été collecté au hasard sur un total de 719 bovins composés de 401 résidents et de 318 semi-sédentaires. Ladétection de trypanosomes a été effectuée grâce à la technique de culture sur couche leucocytaire ; des paramètres sanguins tels que le Volume des cellules sanguines (PCV) (volume de concentrés de globules), la numération des globules blancs (WBC), ont également été déterminés et la comparaison faite entre les infectés des deux groupes. Les résultats ont montré des taux d’infection à trypanosomes de 11% (C.I. = 0.0182, 0.1518) et de 17% (C.I = 0.1287, 0.2113) chez les résidents et le bétail semisédentaires respectivement, bien que la différence n’ait pas été importante du point de vue statistique (P>0.05). Les analyses de sang ont montré que les parasites de trypanosome provoquaient l’anémie, tel qu’en témoignent les baisses en PCV et la leucopénie. Le PCV moyen était de 19% 1,55 SD et 15% 1,40 SD chez les bovins résidents et les bovins semi-sédentaires respectivement, et la différence était importantedu point de vue statistique (P0.05). The blood picture examinations showed that trypanosome parasites produced anaemia as manifested by decreases in PCV and by leucopenia. The mean PCV were 19% 1.55 SD and 15% 1.40 SD in resident and returned cattle respectively and the difference was statistically significant (

Prevalence of Besnoitia besnoiti antibodies in bovine sera and milk in Northern Nigeria

Besnoitia besnoiti, a re-emergent parasite of cattle in Europe, occurs in many countries of Africa and other parts of the world. Clinical observations and incidental findings of B. besnoiti in cattle have been reported in the Southern and Northern regions of Nigeria, but the prevalence of antibodies against this parasite is not yet known. This investigation was designed to determine the seroprevalence of bovine besnoitiosis in Northern Nigeria. A total of 400 cattle were selected at random through cluster sampling of herds from two Local Government Areas (LGA) each, of 5 States in the region (Kano, Kaduna, Katsina, Sokoto and Borno States), between May, 2008 and November, 2009. Sera samples obtained from cows, bulls and calves, and milk from lactating cows with suckling calves were screened with indirect immunofluorescent antibody technique (IFAT) for antibodies to B. besnoiti. Out of the 400 samples 321 (80.3%) were positive for antibodies to B. besnoiti. Cattle sampled in Borno had the highest (87.5%) prevalence of antibodies to B. besnoiti, while those sampled from Katsina State had the least prevalence (62.3%). Wamako LGA of Sokoto State had the highest prevalence of the antibodies (100.0%), while Dan Musa LGA in Katsina had the least prevalence (53.0%) among the ten LGA sampled, however, these differences were not statistically significant (p > 0.05). Similarly, the overall prevalence of antibodies to B. besnoiti did not vary significantly between bulls (84.0%) and cows (79.0%), or in the dry (83.6%) and wet (77.1%) seasons (p > 0.05). The high prevalence of antibodies to B. besnoiti in cattle in Northern Nigeria indicates an endemic state of the disease in this region.Keywords: Antibodies, Besnoitia, Cattle, Northern Nigeria, Prevalenc

Effect of Trypanosoma congolense infection on serum cobalt level in Yankassa sheep

Eighteen (18) Yankassa sheep divided into three groups (A, B and C) of 6 animals each. Groups A and B animals were infected with 2ml x105 Trypanosoma congolense; group A was treated with Berenil® (Hoechst AG, Frankfurt, Germany) at first peak of parasitaemia, while group B animals were left untreated. Blood samples were taken once a week before infection and thereafter twice a week but for parasitaemic determination, it was done daily from the tip of the ears. In all groups, Cobalt (Co) was determined by the use of Atomic Absorption Spectrometer (UNICAM SOLAAR 32). The mean concentrations of Co fluctuated in the course of the experiment with slight decrease in the infected groups, but there was no significant difference (P>0.6553) with those of the control. This indicates that trypanosomosis in Yankassa sheep due to T. congolense has no effect on serum cobalt

Study on the infectivity of Trypanosoma evansi isolate in Savannah brown bucks

No Abstract

The response of serum manganese in Trypanosoma congolense infection in Yankasa sheep

No Abstract

Association of trypanosomes with mortality and morbidity of cattle in the Kachia grazing reserve, Northwest, Nigeria

Short Communication