STUDIES ON THE EFFECTS OF TRYPANOSOMA VIVAX INFECTION ON OVINE PREGNANCY
STUDIES ON THE EFFECTS OF TRYPANOSOMA VIVAX INFECTION ON OVINE PREGNANCY
No Thumbnail Available
Date
2000-01
Authors
BAWA, ELIAS KAMBAI
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Three groups of six pregnant Yankasa and six pregnant West African Dwarf
(WAD) ewes in each group, were assigned at random to first, second and third trimester of
pregnancy study groups, for studies of the clinical manifestation of Trypanosoma vivax
infection, the effects of the infection on pregnancy and the pathological lesions in the dam
and foetuses. The effects of Novidium(R) (homidium chloride) chemotherapy intervention
were also investigated. A group of 3 pregnant Yankasa and 3 pregnant WAD ewes served
as the un-infected controls for the study.
The infection was mild in the Yankasa and WAD ewes infected in their first
trimester, severe in the Yankasa than the WAD ewes infected in their second trimester. In
the third trimester the infection was very severe in the Yankasa ewes, severe in three WAD
ewes and mild in the remaining WAD ewes. The severity of the infection increased as
pregnancy progressed in the Yankasa.
Fluctuating parasitaemia and pyrexia were observed in all the infected Yankasa and
WAD ewes infected in the three trimesters of pregnancy. Anaemia was observed in all the
infected ewes. Significant differences (P<0.05) were observed between the PCV values of
the infected Yankasa and WAD ewes in the second trimester, when the infection was
severe in both breeds. The WAD ewes in this study tolerated the anaemia due to the
infection better than the Yankasa. Decline in body weights were observed in the infected
Yankasa ewes in all the trimesters of pregnancy. Decline in body weights in the WAD
ewes, were observed only in the second and third trimesters of pregnancy. The WAD ewes
in the first trimester showed increase in body weights just as the uninfected control WAD
ewes. Death due to the infection was observed in the Yankasa ewes in second and third
trimester of pregnancy. Death due to the infection was observed in only one WAD ewe and
vi
in the second trimester of pregnancy.
Low foetal weights were observed in the infected-untreated Yankasa ewes in the
first, second and third trimesters of pregnancy. Partial and almost complete foetal
resorptions were observed in the infected-untreated Yankasa in the first and second
trimesters of pregnancy respectively. Abortions were observed in the infected-untreated
Yankasa and WAD ewes, in the third than the second trimester of pregnancy. In the
infected-treated Yankasa ewes, abortions of dead autolysed foetuses were observed in the
first and second trimester. Abortion of a live foetus and a case of dystocia were observed
in the third trimester. The susceptibilty of the Yankasa ewes to the infection increased as
pregnancy advanced in the ewes.
Embryonic death and resorption were observed in the infected-untreated WAD in
the first and second trimesters of pregnancy. Abortions of live foetuses were observed in
the third trimester. The infected-treated WAD ewes in the second and third trimester of
pregnancy carried the pregnancies to term and delivered healthy lambs, in contrast to the
Yankasa.
Pathological lesions in the ovaries, pituitary glands, liver, kidneys and lungs,
observed in the Yankasa and WAD ewes infected in the first and second trimesters of
pregnancy were similar, but differed in severity as influenced by the severity of the
infection and breed of the ewe. Most severe lesions were observed in the second trimester,
when the infection was severe and in the Yankasa than in the WAD ewes. Resolutions of
the gross and histopathological lesions observed in the dam, subsequent to treatment were
early in the infected-treated Yankasa and WAD ewes in first trimester of pregnancy, when
the infection was mild. They were delayed or incomplete in the second trimester when the
infection was severe and in the Yankasa than in the WAD ewes . The success of
chemotherapy in resolution of the pathological lesions in the ewes, was influenced by the
severity of the lesions(due to the severity of the infection) at the time of treatment and the
breed of ewe.
In this study chemotherapy with Novidium(R) at l.Omg/kg body weight,
ameliorated the pathogenic effects of Trypanosoma vivax infection on gestation and
delivery in the WAD ewes. It was therefore concluded from this study that if the
trypanololerancc of WAD ewes is augmented with trypanocidal drugs chemotherapy, the
productivity of the WAD sheep may be enhanced in areas endemic for trypanosomosis.
Description
A Dissertation submitted to Ahmadu Bello University Zaria, in
partial fulfillment for the degree of Doctor of Philosophy in THERIOGENOLOGY.
Department of Veterinary Surgery and Medicine, Ahmadu Bello University Zaria, Nigeria
Keywords
EFFECTS,, TRYPANOSOMA,, VIVAX INFECTION,, OVINE,, PREGNANCY