Plasmodium falciparum gametocytemia in Kenyan children: associations among age, intensity of exposure to transmission, and prevalence and density of subsequent gametocytemia.

Recently, an association was described between the density of Plasmodium falciparum asexual parasitemia in Kenyan children and the entomologic inoculation rate (EIR) measured prior to measurement of asexual parasitemia. This study examined whether transmission pressure, as represented by the EIR, was associated with the prevalence or density of gametocytemia in Kenyan children. Each month for 19 months, a cohort of approximately 50 children was given a radical cure and enrolled in the study.

Impact of transmission intensity and age on Plasmodium falciparum density and associated fever: implications for malaria vaccine trial design.

To facilitate design of vaccine trials, malaria was studied in 6-month- to 6-year-old Kenyans during high (HI) and low intensity transmission seasons. During 84 days after cure, exposure to infected mosquitoes was 9-fold greater in the HI group, yet incidence of P. falciparum infection was increased only 2-fold, with no age effect.

Plasmodium falciparum incidence relative to entomologic inoculation rates at a site proposed for testing malaria vaccines in western Kenya.

Relationships between Plasmodium falciparum incidence and entomologic inoculation rates (EIRs) were determined for a 21-month period in Saradidi, western Kenya, in preparation for malaria vaccine field trials. Children, ranging in age from six months to six years and treated to clear malaria parasites, were monitored daily for up to 12 weeks to detect new malaria infections. Overall, new P.

Diagnosis of Rhodesian sleeping sickness in the Lambwe Valley (1980-1984).

In primary Rhodesian sleeping sickness patients, parasitological diagnosis was best performed by rodent inoculation of blood (98.5%+) followed by Giemsa-stained thick blood smears (93.3%+).

Sleeping sickness in the Lambwe Valley in 1978.

Even though tsetse control measures were discontinued in the Lambwe Valley in 1974 the prevalence of Rhodesian sleeping sickness remained at low levels. A survey conducted in 1978 verified a low prevalence of disease (0.1%).

A history of sleeping sickness in Kenya.

Gambian sleeping sickness entered what is now Kenya from Uganda in about 1901 and quickly spread along the Kenyan shores and islands of Lake Victoria, reaching Tanzania in 1902. By 1910 the disease had spread 25 miles inland along the Kuja and Migori rivers and their tributaries. Sleeping sickness waxed and waned in these areas despite attempts to control tsetse fly populations by various methods.

Treatment of Rhodesian sleeping sickness in Kenya.

In a study of 269 sleeping sickness patients treated with Mel-B, 14 (5.2%) died during treatment. With total dosages of at least 30 ml (1.

Presenting features of Rhodesian sleeping sickness patients in the Lambwe Valley, Kenya.

During a recent outbreak of Rhodesian sleeping sickness in the Lambwe Valley no asymptomatic Rhodesian sleeping sickness patients were found although 54% of the primary patients had mild symptoms and 9% were stuporous or comatose at presentation. The duration of symptoms was three months or less in 90% of the patients. Headache, weakness, joint and back pains and weight loss were claimed by at least 75% of the patients, while 82% of the females reported amenorrhoea and 70% of the males claimed impotency.

Epidemiology of Rhodesian sleeping sickness in the Lambwe Valley, Kenya.

A total of 912 cases of sleeping sickness have been recorded from the Lambwe Valley from 1959 to 1984. After a period of decreasing prevalence in the 1970s an outbreak of disease occurred between 1980 and 1984. The incidence of disease for this five-year period was highest in areas adjoining the Ruma National Park, reaching 54% in Area I.

Demographic characteristics of the Lambwe Valley population.

Thirty-four per cent of the population (11,079) in the Lambwe Valley study site was under the age of 10, and 59% were under the age of 20. The population was equally divided among males and females (M/F 0.99).

Trypanosoma congolense: erythrocyte indices, plasma iron turnover and effects of treatment in infected cattle.

Early during the course of Trypanosoma congolense infection in cattle decreases in PCV occurred and coincided with increases in both MCV and MCH. The indices reached highest levels between eight and 12 weeks post-infection. By week 20 of infection MCV and MCH had decreased to pre-infection levels even though a substantial anemia persisted.

Effects of splenectomy on Trypanosoma congolense infection in cattle.

The role of the spleen in cattle infected with Trypanosoma congolense was studied by comparing levels of parasitaemia, blood cell values, and body weights of intact and splenectomized cattle. A total of 28 Zebu x Hereford steers were used in two separate experiments. Seven animals were splenectomized at least four weeks prior to infection and two others were splenectomized 128 days after infection.

Natural and acquired resistance to Trypanosoma vivax in cattle.

Zebu x European (Z x E) crossbred cattle suffered a more severe course of disease than Boran cattle when infected with Trypanosoma vivax (Likoni) by Glossina morsitans. All Z x E animals in this study required Berenil treatment while all Borans self-cured the infection without treatment. The more severe disease in Z x E animals was characterized by longer periods of patent infection and fever, more severe anaemia and greater likelihood of haemorrhage.

Trypanosoma vivax: disseminated intravascular coagulation in cattle.

Five crossbred cattle infected with Trypanosoma vivax (Likoni) by Glossina morsitans developed capillary haemorrhages at the onset of parasitaemia, followed by the presence of occult blood in faecal samples and eventually melena. Two animals required treatment to survive, on days 13 and 38 respectively. The other three animals cleared their parasitaemias without treatment.

Effectiveness of WR 163577 against animal trypanosomes in goats and mice.

A bisquinaldine, 1,6-bis-(6-amino-2-methyl-4-quinolylamino) hexane, was tested against Trypanosoma brucei ssp. in goats and against T. brucei, T.

Experimental infection of goats with Trypanosoma brucei ssp. and effects of treatment with suramin and Mel-B.

A stock of Trypanosoma brucei ssp. isolated from a naturally-infected goat in the Lambwe Valley, Kenya, induced cerebral trypanosomiasis in experimentally-infected goats. Six of nine goats with cerebral trypanosomiasis induced by this stock were cured by a single high dose of suramin (50 mg kg-1).

Cerebral trypanosomiasis in naturally-infected cattle in the Lambwe Valley, south Nyanza, Kenya.

Surveys in Zebu cattle in the Lambwe Valley in 1980 indicated that many (up to 70%) were infected with trypanosomes. The predominant parasite was Trypanosoma brucei sspl followed by T. congolense.

Experimental infection of cattle with Trypanosoma brucei rhodesiense.

Infection of cattle with various stocks of Trypanosoma brucei rhodesiense indicated that 49% developed a fatal CNS disease comparable to that found in man. Duration of disease ranged from 85 to 1613 days post infection. All eight stocks of T.

The Lambwe Valley and its people.

By 1936 the Lambwe Valley, which had been heavily populated in the early years of this century, was nearly devoid of people. Population since that time has increased markedly as a result of a settlement scheme and efforts made to control and eradicate Glossina pallidipes and trypanosomiasis. The formation of a game reserve (now a National Park) prevented the completion of a tsetse eradication programme and has provided an unmolested habitat for both G.

Review of tsetse control measures taken in the Lambwe Valley in 1980-1984.

During an outbreak of Rhodesian sleeping sickness in the Lambwe Valley in 1980 initial tsetse control measures consisted of applications of dieldrin to the periphery of the Ruma National Park. This activity had a marked effect on the prevalence of sleeping sickness. Concern about the use of dieldrin caused the cessation of this programme and justified an aerial spray programme using endosulfan.

Haemorrhagic syndrome in cattle associated with Trypanosoma vivax infection.

Trypanosoma vivax isolated from dairy cattle undergoing a haemorrhagic disease was inoculated into Ayrshire steers. Five of six infected animals experienced brief periods of diarrhoea and sublingual and gastro-intestinal haemorrhage. Gastro-intestinal bleeding coincided with markedly reduced numbers of thrombocytes and a high level of parasitaemia in the peripheral blood.