O.O. Dipeolu

The presence of kinetes of a Babesia species in the haemolymph smears of engorged hyalomma ticks in Nigeria

Kinetes of a Babesia species were found in the haemolymph smears of 5 species of Hyadomma which were detached from trade cattle after engorgement. Hyalomma rufipes had the highest percentage of infection; while this infection rate was significantly higher than those of H. trupcatum and H. impressum, it was statistically similar to those of H. marginatum and H. impeltatum. Studies on the morphology and dimensions of the kinetes show that they are larger than those of B. bigemina, smaller than those of B. major and B. bovis, but similar to those of B. occultans.

Studies on the blood parasites of pigs in Ibadan, Nigeria

The blood parasites in the blood of local pigs kept under free range, and exotic pigs kept under intensive management of Ibadan were investigated. The species found were Babesia trautmanni, B. perroncitoi, Eperythrozoon suis and E. parvum. Eperythrozoon suis was the most predominant in both breeds. Most of the local pigs carried mixed infections, while the same number of the exotic pigs carried single and mixed infections. Mixed infection of individual pigs with all four blood parasites was common. The parasitaemia was generally low in pigs of both breeds.

Comparison of blood smear and indirect fluorescent antibody techniques in detection of haemoparasite infections in trade cattle in Nigeria.

The incidence of blood parasites in trade cattle was surveyed with emphasis on tick-borne parasites, using blood smears and immunofluorescent antibody (IFA) techniques. With the blood smear method, about 9 and 8.9% of cattle examined were found positive for Babesia bigemina and Anaplasma marginale, respectively. Percentage infections with other parasites were 3.33, 1.92, 0.75, 0.75 and 0.58, respectively, for Babesia bovis, Trypanosoma brucei, Anaplasma centrale, Eperythrozoon and Theileria species as well as Trypanosoma congolense. The incidence of A. marginale infection was at its peak during the rainy season while B. bigemina was most prevalent during the dry season. There were mixed infections of Anaplasma and Babesia (1.42%); Babesia and trypanosomes (1.00%); Babesia and Eperythrozoon (0.75%) and Babesia and Theileria (0.75%). Using the indirect fluorescent antibody test, 93, 55 and 68% of cattle sera examined were found to be positive for B. bigemina, B. bovis and A. marginale, respectively. Forty-nine percent of the positive sera of B. bigemina had highest titres. The importance of using serological means for determining the endemic levels of tick-borne diseases in cattle in Nigeria is discussed.

Parasitic infections of the grey-breasted helmet guinea-fowl (Numida meleagris galeata) in Nigeria

The major helminth parasites found in wild, semi-wild and golden Sovereign stock guinea fowl were Heterakis gallinarum, Ascaridia galli, Capillaria caudinflata, Raillietina tetragona and R. echinobothrida, while Eimeria species was the most important gastro-intestinal protozoan parasite. The incidence of the latter was higher in the semi-wild stock than in the wild stock. Necropsy of dead guinea-fowl indicated that A. galli, H. gallinarum and Eimeria species were indeed responsible for their deaths, especially in the young birds. Parasites found in blood smears were Leucocytozoon sp., Plasmodium sp. and Aegyptianella pullorum. The only tick found, Argas persicus, was on a few semi-wild stock, while lice of genus Damalinia were found only on wild birds.

Studies on ticks of veterinary importance in Nigeria VI. Comparisons of oviposition and the hatching of eggs of Hyalomma species

Fully engorged Hyalomma spp. in Nigeria oviposited greater numbers of eggs than those partially engorged. Hyalomma impressum was a more prolific egg layer than H. rufipes, H. impeltatum and H. truncatum. The variations in the egg output as well as the recognizable peaks in the number of eggs during oviposition were described for each species. No species of Hyalomma below the engorged weight of 0.2 g oviposited; oviposition started with ticks of weight 0.3 g. Eggs produced by ticks weighing below 0.3 g did not hatch; the highest percent egg eclosion occurred with ticks of weight 0.6 g (H. rufipes) and 0.7 g (other Hyalomma species). The pre-oviposition, oviposition and eclosion periods were shortened when eggs were laid and incubated at high temperatures, although the number of oviposited eggs did not increase significantly. At the standard temperature of 24 degrees C, the longest eclosion period was seen in the eggs of H. rufipes (41 days) while those of H. truncatum, H. impressum and H. impeltatum were similar to each other (29 days). Only eggs of H. rufipes hatched at an incubation temperature of 15 degrees C. Eggs of Hyalomma species laid at the same time hatched over a 2--4 day period, except at 15 degrees C when the hatching period of H. rufipes lasted 10 days. The eclosion period was longest in the earlier ovipositions and shorter in the later ones. It is suggested that some intrauterine larval development might have started in the eggs before they were released at a later oviposition period. The percentage mortality of eggs at various temperatures showed that eggs of H. rufipes were more tolerant of low temperatures than those of H. impressum, H. truncatum and H. impeltatum, while the eggs of the latter 3 species were more tolerant of high temperatures than those of H. rufipes. The relevance of these results of the distribution and abundance of the Hyalomma species in Nigeria was discussed.

Strongyle infections of small ruminants in Nigeria.

A survey of strongyle infections was conducted in sheep and goats reared in a traditional extensive husbandry system in two ecological zones of Nigeria. One zone had a seasonal pattern of infection. The majority of animals had faecal worm parasite egg counts of below 500 eggs per gram. Kids, and lambs younger than 3 months did not carry strongyle worm burdens, and the highest infection rate was found in the 7-12 month age group. A high proportion of small ruminants shed strongyle eggs during the postparturient period. The helminth species found by the use of larval culture techniques on the faeces were: Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostomum columbianum. Adults of the same species were found in the few animals necropsied. The significance of the findings is discussed.

Studies on ticks of veterinary importance in Nigeria. XII. Oviposition and eclosion in five species of ixodid ticks in contrasting habitats.

The preoviposition and oviposition periods, the eclosion periods and numbers of eggs laid by adult ticks of five species, namelyAmblyomma variegatum, Boophilus decoloratus, B. geigyi, Hyalomma rufipes andH. truncatum, maintained in a natural habitat were compared with those maintained in semi-natural and artificial habitats. Within the natural habitats, “open” and “shady” sites were distinguished.Maximum oviposition occurred during the peak of the rains in engorgedA. variegatum andB. decoloratus, and the numbers of eggs laid by those kept in the natural and semi-natural habitats were significantly lower in the dry season than in the rainy season. Maximum oviposition in engorgedH. rufipes kept in the natural habitat occurred during the early rains while minimum oviposition took place during the peak of the rains.Oviposition in engorgedH. truncatum was poor among those kept in the natural habitat during the peak and end of the rains. EngorgedA. variegatum andB. decoloratus kept in shady sites of the natural habitat laid significantly more eggs than in all other habitats at all seasons, while forH. truncatum andH. rufipes, numbers of eggs laid in the open site were significantly higher than those laid in other habitats at all seasons.In all species investigated, success in oviposition was aided by moisture provided by light to moderate rainfall, while excessive moisture in terms of heavy rainfall adversely affected oviposition.

Studies on ticks of veterinary importance in Nigeria XI. Observations on the biology of ticks detached from the red-flanked duiker (Cephamophys rufulatus) and parasites encountered in their blood

Some aspects of the biology of Amblyomma variegatum and Boophilus decorolatus detached from red-flanked duikers were studied. Smears were also made from the blood of the duikers and examined for the presence of parasites. Anaplasma marginale was the only blood parasite found in the blood smears. Compared with ticks detached from cattle, duiker ticks produced a greater number of eggs. The lengths and breadths of eggs produced by duiker ticks were greater than those of cattle ticks and unlike A. variegatum detached from cattle, the lengths and breadths of eggs of earlier and later ovipositions of this species detached from duiker were similar. Whereas deformed eggs characterised by circular shape and small size constituted a small percentage of eggs of cattle ticks, none was found among eggs of duiker ticks. The pre oviposition, oviposition and eclosion periods, microscopic egg structure, embryonic development, hatching patterns and mortality rates of the eggs of ticks from both hosts were similar.

Transmission of Anaplasma marginale from a naturally-infected wild african giant rat (Cricetomys gambianus), waterhouse) to a calf in Nigeria

Abstract Blood taken from an African giant rat in Nigeria, transmitted Anaplasma marginale when inoculated into a splenectomised calf. The infection of the calf was sub-clinical and the highest percentage of infected erythrocytes recorded was 6. Anaplasma marginale was first observed in the calfs blood three days after inoculation, but the parasite disappeared suddenly, nine days after inoculation. This is the first experimental demonstration of A. marginale infection in African giant rats in Nigeria, a country where anaplasmosis is endemic in the cattle population. The significance of giant rats being a reservoir host of A. marginale in Nigeria is discussed.

Prevalence of Anaplasma marginale, Babesia bigemina and B. bovis in Nigerian cattle using serological methods

Serum samples collected randomly from 500 cattle from the 10 northern states of Nigeria were tested for antibodies against Anaplasma marginale by indirect fluorescent antibody (IFA), card agglutination (CT) and capillary tube-agglutination (CA) tests. The serum samples were also examined for antibodies to Babesia bigemina and B. bovis by the IFA test only. Of the serum samples tested, 79.4% had antibodies against A. marginale by the IFA test, 40 and 25% in the CT and CA tests, respectively. The IFA test results for B. bigemina and B. bovis were 29.4 and 14.1%, respectively.