Studies of infectivity and pathogenicity of an isolate of Trypanosoma evansi in Yankasa sheep

Audu, PA; Esievo, K. A. N.; Mohammed, Garba; Ajanusi, O.J.

doi:10.1016/s0304-4017(99)00141-7

Cited by 30 publications

(14 citation statements)

References 12 publications

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“…The clinical signs observed in rabbits experimentally infected with T. evansi in the present study were in agreement with the reports of Chandra et al (1999), Audu et al (1999), Dargantes et al (2005), Taiwo et al (2003). Decreased values of TEC, Hb and PCV in the study might be due to increased susceptibility of red blood cell membrane to oxidative damage (Taiwo et al 2003).…”

Section: Discussionsupporting

confidence: 83%

“…Decreased values of TEC, Hb and PCV in the study might be due to increased susceptibility of red blood cell membrane to oxidative damage (Taiwo et al 2003). Similar observations were made by Audu et al (1999), Herrera et al (2002), Hilali et al (2006). In the present investigation, anaemia is the most consistent finding which is in accordance with Taiwo et al (2003), Takeet and Fagbemi (2009).…”

Section: Discussionsupporting

confidence: 77%

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Haematological and biochemical changes in experimental Trypanosoma evansi infection in rabbits

Sivajothi

Rayulu

Reddy³

2013

J Parasit Dis

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New Zealand white rabbits (N = 4) were challenged with the local strain of Trypanosoma evansi. Each rabbit was infected with 5 9 10 5 trypanosomes subcutaneously. The infection was characterized by intermittent pyrexia, undulating parasitaemia, anorexia and emaciation. The infected rabbits were examined daily for development of clinical signs and infection status by wet blood-films made from the ear veins. Thick and thin blood smears were also examined daily until the end of the experiment for description of blood cells. Differential leukocyte count (DLC) was also done. The parasite was observed in the blood during the acute phase only. Leukocytosis in the acute phase followed by leukopenia during the chronic phase was recognized. Haematological studies revealed reduced TEC, Hb and PCV. The main changes in the erythrocytes were macrocytes, hypochromic cells, Howell-Jolly bodies, target cells, stomatocytes and burr cells. Serum chemistry revealed hypoproteinemia, hypocholesterolaemia, hypoglycemia, hyperbilirubinemia, elevated creatinine, BUN, increased AST and ALT.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionsupporting

confidence: 77%

Haematological and biochemical changes in experimental Trypanosoma evansi infection in rabbits

Sivajothi

Rayulu

Reddy³

2013

J Parasit Dis

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“…The Djallonke sheep is a West Africa Dwarf sheep found in Gambia and are generally known to be trypanotolerant surviving in tsetse infested areas (7). In contrast, the Yankasa breed used in this study are highly susceptible to trypanosomosis (2,5,33).…”

Section: Discussionmentioning

confidence: 98%

Effects of Experimental Trypanosoma Congolense Infection on Sperm Morphology in Yankasa Rams

Okubanjo

Sekoni

Ajanusi

et al. 2015

Macedonian Veterinary Review

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The objective of the study was to determine the effect of T. congolense on the sperm morphology of Yankasa rams (YKR). Nine YKR aged 24-30 months-old were assigned into two groups of 6 infected and 3 uninfected control and were monitored for 7 weeks. The infected group of YKR was each inoculated with 1 x 10 6 T. congolense through the jugular vein, while the control group remained uninfected. The entire infected group developed trypanosomosis post infection (pi) characterized by sperm morphological abnormalities in the semen. There were significant (P<0.001) increases in the mean percentage of acrosomal, head, middle piece and tail abnormalities. Proximal and distal droplets as well detached heads were also significantly (P<0.001) increased post infection (pi). Acrosomal abnormalities, distal droplet and tail abnormalities increased from week 1 pi till the end of the study, while head abnormalities and detached heads increased from week 2 pi. Middle piece abnormalities and proximal droplets increased from week 3 and 4 pi till the end of the study respectively. The high incidence of morphological defects caused by T. congolense is capable of causing infertility from the first week pi thereby making the rams unfit for breeding at the end of the study.

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“…But the spleen tends to swell in a sick animal as it helps fight parasites or other pathogens, as in Yankasa sheep (Audu, Esievo, Mohammed, & Ajanusi, 1999) and Montane voles (Watkins, Moshier, Odell, & Pinter, 1991). So, in infected animals, the amount of swelling of the spleen was used as an indicator of the cost in immune function associated with infection with T. evansi.…”

Section: Field Proceduresmentioning

confidence: 99%

Trypanosoma evansi (Kinetoplastida: Trypanosomatidae) in capybaras (Hydrochoerus hydrochaeris, Rodentia: Hydrochoeridae): prevalence, effect and sexual selection

Herrera¹,

Castro²

2017

RBT

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Parasites play a crucial role in the ecology of animals. They also appear to be important in mechanisms underlying sexual selection processes. In this article we study the prevalence, effect and potential role in sexual selection of the protozoon Trypanosoma evansi in capybaras, Hydrochoerus hydrochaeris. We collected our samples from the annual capybara cull of a ranch in Venezuela, using the volume of the snout scent gland as an indicator of dominance; the residuals of body weight as indicators of condition; and the residuals of the spleen mass as indicators of immune function. Overall prevalence was 30.9 % (N= 97) with no difference between males and females, and no relation between infection with T. evansi and condition. However, we found that infected animals had larger spleens (residuals), indicating an immunological cost of the infection. Furthermore, males with larger snout scent glands (more dominant) were less likely to be infected than males with smaller glands (less dominant), suggesting that by choosing males with a large glands, females may be using the gland as an indicator of health, which is consistent with the "good genes" view of sexual selection. Rev. Biol. Trop. Parasites are important factors in the dynamics of their host's populations (Pedersen & Greives, 2008) by affecting their survival, reproduction (Albon et al., 2002) and behavior (Berdoy, Webster, & Macdonald, 2000). However, suspected parasites can often be commensals or even mutualistic symbionts (Ewald, 1987). Even when clear phenotypic effects of a parasitic infection are not apparent, an infection can carry a significant immunological cost (Lochmiller & Deerenberg, 2000). Parasites have also been hypothesized as central role players in the process of sexual selection. Thus, Hamilton and Zuk (1982) have argued -and presented evidence-that it is advantageous for a male bird to advertise his lack of parasites by developing and showing off bright coloration in his plumage. Such a display, being costly, would be an honest signal of condition which females could use to choose good quality males (Grafen, 1990;Keyser & Hill, 2000). In mammals, other features such as antlers or manes may play the same role as do colors in birds. In particular, the development of a scent gland and scent marking behavior may be subject to sexual selection (e.g. bats, Voigt et al., 2008; review by Penn & Potts, 1998) and may function as honest signals of health (Zala, Potts, & Penn, 2004).Capybaras, Hydrochoerus hydrochaeris (Linnaeus, 1758), large (50 kg), grazing rodents, are common in the savannahs and wetlands of tropical and subtropical South America (Ojasti, 1973), where they live in stable social groups composed of both males and females, with an average of 3-4 male and 6-7 female adults per group (Herrera & Macdonald, 1987;Herrera, Salas, Congdon, Corriale, & Tang-Martínez, 2011). In these groups, a clear-cut and long-lasting dominance hierarchy is evident among the males: the dominant male is usually able to win all encounters against m...

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Studies of infectivity and pathogenicity of an isolate of Trypanosoma evansi in Yankasa sheep

Cited by 30 publications

References 12 publications

Haematological and biochemical changes in experimental Trypanosoma evansi infection in rabbits

Haematological and biochemical changes in experimental Trypanosoma evansi infection in rabbits

Effects of Experimental Trypanosoma Congolense Infection on Sperm Morphology in Yankasa Rams

Trypanosoma evansi (Kinetoplastida: Trypanosomatidae) in capybaras (Hydrochoerus hydrochaeris, Rodentia: Hydrochoeridae): prevalence, effect and sexual selection

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