5 research outputs found
Studies on Onchocerca gutturosa (Neumann, 1910) in Sudanese and British cattle.
Onchocerca gutturosa is prevalent in Sudanese cattle,
and aspects of its behaviour, transmission, and morphology
were studied and where possible comparisons have been made
with the same species in U. K. A vector, Culicoides kingi,
was discovered and the complete development of 0. gutturosa
was studied.
The adult worms were found to inhabit the'ligamentum
. nuchae and stifle joint. None were found in the gastrosplenic
ligament. All adults and microfilariae found were
0. gutturosa (Neumann, 1910). The microfilarial distributions
in the skin around the hump region in Sudanese cattle
contrasted sharply with those'reported in English cattle,
presumably an adaptation to the biting habits of C. kingi
in the Sudan.
Pathological effects of 0. gutturosa in the ligamentum
nuchae of cows were minor. Distinct morphological differences
were found between microfilariae in the uterus of adult
worms and those in the dermis of cows. Those emerging from
the uterus of adult females did not develop in the vector.
There were also two forms of microfilariae in the uterus of
adult females which appeared to represent two stages of
maturity.
In the skin of Sudanese cattle microfilariae of
0. gutturosa were found in the"same region as microfilariae
of 0. armillata and of 0. raillieti in donkeys. Microfilariae
of 0. gutturosa could be readily distinguished from the other species by differences in size, number of
nuclei anterior to the nerve ring and in arrangement of the
caudal and cepkhalic nuclei.
C. kingi was discovered to be a vector at a dairy
farm near Khartoum. Although the midge showed seasonal
changes in abundance, there was no clear seasonal variation
in number of microfilariae found in the dermis of Sudanese
cattle. However, maximum numbers of microfilariae coincided
with maximum activity of C. kingi. Biting activity of
the midge showed 2 daily peaks. Ninety five per cent of
the attacking C. 'kingi landed on the back of the cow and
25% were successful in obtaining a blood'meal. The
attractiveness of the hump surface was related to the lack
of-hair and less host disturbance.
Complete adult 0. gutturosa were obtained from Sudanese
cattle using a digestion technique. Living male and female
worms were transplanted into the peritoneal cavity of
different strains of mice; some survived up to 133 days.
The behaviour of 0. gutturosa microfilariae in the
Nile rat and in mice was studied for a screening model.
Chemotherapy was also carried out in naturally infected
cattle