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Biomedical subjects

F Jongejan

Publications and source records attributed to F Jongejan.

118 records · Page 7Linked to original sources
PubMed1984

Cultivation of Theileria. I. Attempts to complete the cycle of Theileria parva in vitro.

Microschizonts and free merozoites developed in bovine lymphoblastoid cell cultures containing macroschizonts of 6 different strains of Theileria parva. Clean bovine red cells were added to the cultures, which were incubated in various ways. No penetration of red cells by merozoites was observed, not even when cultures in diffusion chambers were introduced into the peritoneal cavity of non-infected cattle.

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PubMed1984

Cultivation of Theileria. II. Attempts to cultivate erythrocytic stages of Theileria mutans.

Blood from calves with a parasitaemia of Theileria mutans was cultivated in vitro in various ways. No significant increase in the percentage of infected red cells was observed, but the percentage of dividing forms of the parasite rose sharply during the first two days of incubation. The conditions of the cultures were apparently unsuitable for the invasion of erythrocytes.

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PubMed1984

Isolation and transmission of Theileria mutans (Chisamba) in Zambia.

Theileria mutans (Chisamba) was isolated from a steer at Chisamba, Central Province, Zambia by inoculation of blood into a susceptible unsplenectomised calf. The parasite was then transmitted on three occasions by nymphs and once by adult Amblyomma variegatum ticks. Macroschizonts, typical for T mutans, were detected in two calves for short periods. The parasite caused varying degrees of anaemia in all experimental calves, whose sera showed high antibody titres to T mutans in the indirect fluorescent antibody test.

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PubMed1983

Infection rates of Theileria annulata in the salivary glands of the tick Hyalomma marginatum rufipes.

Theileria annulata was experimentally transmitted to cattle on two occasions by the two-host tick Hyalomma marginatum rufipes. Transmission was transstadial; engorged nymphs fed on Theileria annulata-infected calves transmitted the disease as adults. Salivary glands of all partially fed and incubated adult ticks were heavily infected with Theileria parasites. Immatures attached rapidly and fed successfully on cattle. However, since the immature stages of this species normally feed on birds, this tick is unlikely to be an important vector in the field.

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PubMed1983

Natural infection rates of Hyalomma anatolicum anatolicum with theileria in Sudan.

Hyalomma anatolicum anatolicum ticks were collected around cattle pens at two locations close to Khartoum. They were assessed for theileria infection by four methods. Salivary glands were stained whole with methyl green pyronin and examined for parasite masses. Adult ticks were partially fed on rabbits, ground up in medium, and the suspensions were examined in Giemsa stained smears and by inoculation into bovine lymphocyte cultures. Ticks were fully fed on calves which were monitored for developing theileriosis. H a anatolicum were found infected with parasite masses similar to those seen in experimental infections with T annulata. At one site 38 per cent of 102 ticks were infected and the mean number of parasite masses per tick for the whole sample was 37. At the other site 86 per cent of 156 ticks were similarly infected and the mean parasite masses per tick was 19.5. Suspensions of sporozoites contained sporozoites typical of those found in experimental preparations of T annulata. Sporozoites harvested from ticks from both locations infected and transformed normal bovine lymphocyte cultures. H a anatolicum ticks from both locations produced fatal theileria infection in susceptible calves.

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PubMed1982

The influence of various bovine sera on the maintenance of Theileria parva lymphoblastoid cell culture.

Theileria parva infected lymphoblastoid bovine cells were grown in a medium based on HEPES-buffered RPMI 1640 with glutamine and antibiotics, supplemented with bovine serum. There were no significant differences in growth rate, viability, and percentage of infected cells when the substrate contained 10 or 20 per cent of either commercially available newborn calf serum of serum prepared from adult non-infected Friesian cattle or of serum prepared from a Friesian calf immunised against East Coast fever and having a high titre of antibodies to T. parva antigen in the indirect fluorescent antibody test. If studies showing that newborn calf serum gives results in the establishment and maintenance of T. parva cell culture similar to those of foetal calf serum are confirmed, this finding could mean an appreciable saving in the cost of in vitro work on this parasite.

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PubMed1980

Artificial infection of Rhipicephalus appendiculatus with Theileria parva by percutaneous injection.

Rhipicephalus appendiculatus nymphs were inoculated with fresh or cryopreserved blood containing Theileria parva piroplasms, or with cell culture grown stages of T parva. The use of fresh blood was successful. Cryopreserved blood containing dimethylsulphoxide (DMSO), killed most nymphs after inoculation: DMSO could be removed by slow dialysis, without destroying the infectivity of the blood. Attempts to infect ticks by inoculating cell culture grown stages of T parva failed, even when large numbers of merozoites were present in the inoculum.

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PubMed1980

Cowdria ruminantium (Rickettsiales) in primary goat kidney cell cultures.

Fresh or cryopreserved kidney tissue from goats suffering from heart water (Cowdria ruminantium infection) was infective when inoculated intravenously into susceptible goats. Primary kidney cell cultures were established from 14 goats reacting to C ruminantium infection; they were tested for infectivity by intravenous injection into susceptible goats after periods varying from five to 31 days. Three cultures, five, 12 and 13 days old, induced heartwater in recipients. The other 11 cultures, varying in age from six to 31 days, did not cause any reaction and all 11 recipient goats died from heartwater on challenge. C ruminantium could not be detected microscopically in the cell cultures.

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