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Biomedical subjects

P F Boreham

Publications and source records attributed to P F Boreham.

At least 73 records · Page 4Linked to original sources
PubMed1984

Activation in vitro of some biological systems by extracts of adult worms and microfilariae of Dirofilaria immitis.

Extracts of Dirofilaria immitis adults and microfilariae cause the degranulation of mast cells in rat mesentery when applied in vitro and also cause increased vascular permeability in guinea-pigs and rabbits. Adult worms but not microfilariae are able to activate complement in vitro and both stages contain a plasminogen activator. No proteolytic activity or haemolysins could be detected in either stage. The possibility that these factors may be important in the pathogenesis of dirofilariasis and in the adverse drug reactions that may follow treatment of microfilaraemic animals with diethylcarbamazine is discussed.

Animals↗
PubMed1984

The sensitivity of Giardia intestinalis to drugs in vitro.

Techniques are described for the isolation, microculture and assessment of viability of Giardia intestinalis. The susceptibility of five recent Brisbane isolates and the Portland 1 stock to metronidazole, tinidazole, furazolidone and quinacrine has been determined. All stocks showed little variation in sensitivity to these drugs. The 3H-thymidine incorporation assay proved to be a much more sensitive method of assessing relative drug activity than either motility or dye exclusion methods. Tinidazole proved to be the most effective drug in vitro followed by furazolidone and metronidazole. Quinacrine was the least effective. The generation time of stocks in vitro varied from 12.5 to 44.2 h and the possible significance of this to failures in treatment is discussed.

Antiprotozoal Agents↗
PubMed1982

A preliminary investigation of the effect of age, sex and time of collection on the feeding patterns of Glossina morsitans morsitans Westw. in Zambia.

Glossina morsitans morsitans were collected during the dry season of 1975 from two areas in the Luangwa Valley (Zambia) and from one of the areas in the wet season of 1976. In all, 1,190 flies were analysed for sex, wing fray category and source of bloodmeal. Differences in the feeding patterns in the morning and afternoon collections reflected host behaviour. Warthog consistently emerged as a major host but there appeared to be some local variation resulting from seasonal and diurnal availability of hosts.

Age Factors↗
PubMed1981

Haptoglobin polymorphism and its relationship to malaria infections in The Gambia.

The haptoglobin (Hp) status of the population of Keneba, The Gambia was investigated. Of the 825 persons examined 22.9% were ahaptoglobinaemic (HpO). The incidence of HpO was higher in the 209 persons showing malaria parasites in their blood (38.8%) than in non-parasitaemic individuals (17.5%). Children less than two years old had low incidences of HpO except in the first two months of life. After two years the incidence rose with little tendency to change in older age groups. No correlations were seen between HpO and sex, anaemia or sickle cell trait. However, a positive correlation was found with malariometric indices in all age groups except the two to four years. The Hp of individuals was found to be unstable suggesting that in Africans it is a poor genetic marker. These results indicate that Hp is utilized in removing free haemoglobin liberated intravascularly, during malaria infections and that although this is a major cause of the high incidence of HpO in The Gambia, other factors are also important.

Adolescent↗
PubMed1980

Studies on Glossina pallidipes, G. fuscipes fuscipes and G. brevipalpis in terms of the epidemiology and epizootiology of trypanosomiases in south-eastern Uganda.

Glossina pallidipes, G. f. fuscipes and G. brevipalpis in Stages I and II of hunger were caught from Bukunya and Buyundo villages in south-east Uganda during the period December 1969 to February 1971, and the origins of their blood meals identified. G. pallidipes fed mainly on bovids in the two villages; bushbuck was the most favoured host (44.9% of all blood feeds) though in Buyundo buffalo provided a significant alternative (20.8%). G. f. fuscipes frequently fed on bovids (75.6%), particularly bushbuck (46.7%), but it had a wider range of acceptable hosts. In both villages, G. brevipalpis took most of its blood meals from bushpig (45.5%), bovids (25.6%) and hippopotamus (28.5%). The feeding patterns of the three tsetse species during different months of the study period showed only small variations, and such differences were due probably to variations in the availability of the hosts. Examination of the relationships between trypanosome infection rates and natural hosts of the three vector species showed that the vivax-type infections originated from bovids, possibly bushbuck, while the congolense-type trypanosome came from bovids as well as bushpig. Hippopotamus probably had no trypanosome infections. There was a positive correlation between the trypanosome infection rates in the tsetse and the increasing mean maximum temperatures. In this region of Uganda, there was continuous transmission of pathogenic trypanosomes by the three tsetse species among their natural hosts; when present, the vectors' adventitious hosts became exposed to a high risk from the diseases. Man-fly contact during different months was impersonal, but high and sporadic. This is a high endemic region for human trypanosomiasis. Also, the introduced cattle succumb to the diseases very rapidly. The overall results are discussed in terms of the concept of challenge of African trypanosomiases.

Animal Population Groups↗
PubMed1979

Studies on multiple feeding by Anopheles gambiae s.l. in a Sudan savanna area of north Nigeria.

The detection of haptoglobins in Anopheles gambiae s.l. has been used to obtain an estimate of the incidence of multiple feeding for the village of Barmawa, Garki District, Kano State, Nigeria. The results indicated that the incidence of multiple feeding was approximately 10% but problems were encountered by the high incidence of ahaptoglobinaemia in the population. In four villages in Garki District the incidence of ahaptoglobinaemia varied between 65 and 76% while in young children and personnel under constant malaria chemoprophylaxis it was less than 30%. A strong correlation between ahaptoglobinaemia and malaria infections was seen. The results show evidence of selection of hosts by mosquitoes at Barmawa although this does not necessarily imply a preference per se. The results provide evidence of movement of blood-fed mosquitoes, between houses and from houses to resting sites.

Animals↗
PubMed1979

Host selection patterns of some Pakistan mosquitoes.

The host selection patterns of 18 species of Pakistan mosquitoes are described, emphasizing the presumed malaria vectors, Anopheles culicifacies, An. fluviatilis, and An. stephensi, and the probable vectors of West Nile virus, Culex pipiens fatigans and Cx. tritaeniorhynchus. All species tested, with the exception of Cx, p. fatigans, were considered to be essentially zoophilic. Few human feeds were recorded for An. annularis (0.7%), An. culicifacies (0.5%), An. fluviatilis (1.1%), An. nigerrimus (14.3%), and Cx. bitaeniorhynchus (2.8%), while Cx. p. fatigans (37.6%) commonly fed on man. No human positive feeds were recorded for An. stephensi. Temporal or spatial changes in host selection patterns were not discerned with the exception of Cx. p. fatigans, whose feeding patterns varied opportunistically with host availability. Cx. p. fatigans females collected from houses fed more commonly on man than those resting in cattle sheds or in agricultural fields. Cx. p. fatigans resting in cattle sheds during winter fed mostly on birds and bovids, changing to man and bovids during the spring and then to man and birds during summer. The relationships between these results and vector-borne disease transmission in Pakistan are discussed.

Animals↗
PubMed1979

The feeding habits and ecology of the tsetse fly Glossina morsitans submorsitans Newstead in relation to nagana transmission in the Gambia.

The source of blood meals from 174 fed Glossina morsitans submorsitans Newstead, captured in malaise traps in Savanna woodland in The Gambia, were identified by the precipitin test. Warthog accounted for 90% of the meals and single bushbuck and ox feeds were identified. Nagana is a major problem in the area, but contact between tsetse and livestock is reduced by restricted grazing. In this situation, warthog, with a ubiquitous distribution, appear to be major maintenance hosts for G. m. submorsitans as well as a potential reservoir of trypanosomiasis.

Animals↗
PubMed1978

The incidence of mosquitoes feeding on mothers and babies at Kisumu, Kenya.

Blood fed mosquitoes were collected inside four bed nets in which mother/child pairs, having different haptoglobin types, slept. The bloodmeals were analysed by gradient gel electrophoresis to determine on which person the mosquitoes had fed. The results suggest that the mothers are fed on much more than babies by both Anopheles gambiae s.l. and Culex fatigans. In one hut at least 15.2 per cent of the mosquitoes had taken all or part of their bloodmeal elsewhere. A greater number of double feeds were detected from engorged Cx. fatigans (12.6%) than An. gambiae s.l. (2.7%).

Anopheles↗
PubMed1977

Studies on the feeding patterns of the sheep headfly Hydrotaea irritans (Diptera, Muscidae) in Great Britain.

Serum-precipitin tests carried out on the stomach contents of laboratory maintained and field-caught Hydrotaea irritans showed that a positive result could be obtained for at least seven to 10 days after feeding. Eye, nasal and salivary secretions, even if undiluted, did not give a precipitin response in these tests. Field results from over 3000 flies thus indicate that 20 to 55% of the active fly population had taken a blood meal within the previous 10 days: 75 to 100% of these had fed on cattle blood and 15% or less on sheep blood. Significantly lower feeding levels were obtained from flies collected within plantations, indicating a protracted resting phase in woodland. From "fly feeding areas" high blood-feeding levels were shown from early July, as ovarian development begins. Early feeding rates were similar in both sexes.

Animals↗