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Biomedical subjects

G Uilenberg

Publications and source records attributed to G Uilenberg.

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

Animals↗
PubMed1982

Heartwater (Cowdria ruminantium infection) on São Tomé.

The supernatant obtained after centrifugation of an emulsion of engorged female Amblyomma astrion ticks, collected from cattle on the West African island of São Tomé, was injected intravenously into a goat, which contracted heartwater. This confirmation of the existence of the disease on the island makes strict control measures necessary if present efforts at improving livestock production by imported exotic cattle are to be successful.

Animals↗
PubMed1982

Experimental transmission of Cowdria ruminantium by the Gulf coast tick Amblyomma maculatum: danger of introducing heartwater and benign African theileriasis onto the American mainland.

The tick Amblyomma maculatum proved to be an experimental vector of Cowdria ruminantium, the cause of heartwater of ruminants. Transstadial transmission from larva to nymph and from larva through nymph to adult was successful; however, an experiment on transovarial transmission gave negative results. Neither A americanum nor A cajennense transmitted the infection. There is a potential danger of the disease gaining access to the American mainland from the Caribbean where it is known to occur and of maintaining itself in areas where A maculatum occurs. Transstadial transmission experiments, using 3 American Amblyomma spp and an African strain of Theileria mutans, which is thought to occur in the Caribbean, were unsuccessful.

Africa↗
PubMed1981

Theileriosis in Uganda. Parasitological and serological responses in cattle continually exposed to natural infection.

Cattle living in a circumscribed area in Uganda, where both Theileria parva and T. mutans occurred naturally, were monitored for periods of up to 1 year by examination of blood and lymph node smears for parasites and the indirect fluorescent antibody test for antibodies to Theileria. Uninfected control cattle were added at intervals to ensure continuous challenge and to monitor the challenge. Although all 29 control animals became infected with T. parva, challenge was light at first as mortality from theileriosis only commenced in the 18 introduced after day 138 of the study; 14 of these died of the disease. Most of the 34 animals in the original group appeared to be susceptible to T. parva at the start of the study and 6 died of theileriosis. All animals were, or became, infected with T. mutans. Several animals exhibited patent T. parva infections on more than 1 occasion and 1 died from the second infection indicating the existence of immunologically different strains. Recovered animals appeared to acquire eventually a solid immunity to the local Theileria strains but 9 of the original animals and 7 of the controls died exhibiting massive tick and helminth burdens, sometimes aggravated by the effects of previous T. parva and/or T. mutans infections.

Animals↗
PubMed1981

Babesia crassa n.sp. (Sporozoa, Babesiidae) of domestic sheep in Iran.

A large Babesia sp., isolated from a sheep in Iran, provided to be serologically and morphologically different from B, motasi and B. ovis. The parasite, designated B. crassa n. sp., is characterized by the frequent occurrence of four organisms in one erythrocyte, which is the result of quadruple division and, in other cases, of two successive binary divisions. Parasited resulting from the first of two successive binary divisions are exceptionally broad. B. crassa appears to be of low pathogenicity for sheep and goats, to which it is also infective. The vector is unknown.

Animals↗
PubMed1981

Isoenzyme studies on Theileria (Protozoa, Sporozoa). Enzyme activity associated with the erythrocytic stage.

Bovine blood containing piroplasms of Theileria parva, as well as non-infected blood, was lysed and subjected to iso-electric focussing. Staining for 13 different enzymes revealed parasite-associated bands of glucose phosphate isomerase (GPI) activity, not of any of the other enzymes. There were no variations between individual donor animals in the host cell GPI bands and these bands did not interfere with the recognition of the parasite-associated bands, so that purification of the piroplasms was unnecessary. Blood from cattle infected with T. mutans also gave parasite-associated bands of GPI, but no such bands were seen in zymograms of blood from cattle infected with a Theileria sp. from Japan. Dependent on the level of parasitaemia, up to four parasite-associated bands were found in one strain of T. parva and up to three in two other strains. Among the disadvantages of using piroplasm material for the study of isoenzymes of T. parva is the fact that animals often die before their parasitaemia is sufficiently high, and that some strains never give rise to a high parasitaemia.

Animals↗
PubMed1981

Imidocarb: a chemoprophylactic experiment with Babesia canis.

Eight dogs, given imidocarb dipropionate subcutaneously at a dose of 6 mg/kg, were challenged with a sporozoite stabilate of a French strain of Babesia canis, prepared from infected Dermacentor reticulatus ticks, 2, 3, 4 or 5 weeks after treatment. Three control dogs were similarly infected but not preventively treated. One of the controls and one of the dogs treated 5 weeks prior to challenge died of babesiosis. Prepatent and incubation periods were similar in treated and control dogs, and all dogs showed important reductions in the packed cell volume. Relapses were commonly seen after recovery from the initial reaction. Although further work is needed before a final conclusion can be drawn to whether imidocarb is suitable as a chemoprophylactic against B. canis infection, it can be used as a curative drug.

Amidines↗
PubMed1980

Blood parasites of sheep in the Netherlands. II. Babesia motasi (Sporozoa, Babesiidae).

A large Babesia species occurs in sheep on the North Sea islands of the Netherlands. The tick Haemaphysalis punctata is a vector. Its pathogenicity appears to be low. It is morphologically similar to a Turkish strain, considered to be B. motasi, which is also transmitted by Haemaphysalis ticks. It differs from the Turkish parasite serologically as well as in cross-immunity tests and in not being effective to goats. There may be a group of morphologically similar parasites with serological differences and different infectivity for sheep and goats. As it is impossible to know which one is to be considered as the original B. motasi, we designate the Dutch parasite as B. motase (Netherlands). Anaplasma mesaeterum was found to occur on the island of Texel as well as on Ameland, where it had been found initially.

Animals↗
PubMed1980

Development of Theileria mutans (Theiler, 1906) in the gut and the haemolymph of the tick Amblyomma variegatum (Fabricius, 1794).

The development of Theileria mutans in the gut and haemolymph of its tick vector, Amblyomma variegatum, was studied by Giemsa-stained smears after the nymphal tick had completed engorgement on parasitaemic calves. Sexual stages occurred in the gut between five and seven days after repletion. The zygotes were observed in the gut from day 29 and the kinetes from day 30, i.e. three and four days after the nymphs moulted to adults. From day 34 kinetes were observed in the haemolymph. The developmental stages of T. mutans in the tick were compared with those of other Theileria spp. of cattle.

Animals↗
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.

Animals↗
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.

Animals↗
PubMed1979

Blood parasites of sheep in the Netherlands. I. Anaplasma mesaeterum sp.n. (Rickettsiales, Anaplasmataceae).

On two occasions an anaplasm was isolated from sheep on the Dutch island of Ameland. The organism proved to be highly pathogenic for splenectomised sheep; a non-splenectomised animal recovered spontaneously after the packed cell volume had decreased by 40%. Treatment with oxytetracycline was effective. Its pathogenicity for goats appeared to be low, and the organism was apparently not infective to splenectomised cattle. This anaplasm differs from Anaplasma ovis in that less than 30% of the organisms are marginally situated in the red cell, as against over 70% in A. ovis; cross-immunity with A. ovis was incomplete and the latter appeared to be far more pathogenic to goats than the Dutch anaplasm, for which the name Anaplasma mesaeterum sp.n. is proposed. Its ultrastructure is similar to that of A. marginale and A. ovis. The vector is either Ixodes ricinus or Haemaphysalis punctata. Its practical importance remains to be ascertained.

Anaplasma↗
PubMed1979

Theileria mutans in Nigeria.

Two strains of bovine Theileria from northern Nigeria were shown to be identical to Theileria mutans in the indirect immunofluorescent antibody test. One of the strains was transmitted by the tick Amblyomma variegatum; large macroschizonts, typical for T mutans, could be demonstrated in infected cattle. It is concluded from these experiments and from the literature that there is reliable evidence so far for the occurrence in Nigeria of only two bovine Tehileria species, T mutans and T velifera.

Animals↗