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Biomedical subjects

M Samish

Publications and source records attributed to M Samish.

At least 37 records · Page 2Linked to original sources
PubMed1995

Factors affecting membrane feeding of Anopheles stephensi.

The impact of optimal temperature, osmotic pressure, and diet viscosity on the number of mosquitoes (Anopheles stephensi) feeding through a membrane, and on the size of the blood meal, was evaluated. An increase in diet viscosity decreased the number of imbibing mosquitoes, reduced the size of the ingested meal, and resulted in a slower rate of weight loss after feeding. The possible effect of these factors on the vectorial efficiency of mosquitoes is discussed.

Animal Feed↗
PubMed1993

Intrastadial and interstadial transmission of Anaplasma marginale by Boophilus annulatus ticks in cattle.

The 1-host tick Boophilus annulatus was found to transmit anaplasmosis in cattle transstadially. Anaplasma marginale was invariably transmitted when ticks that had been pulled off Anaplasma-infected calves either after 7 days (as fully engorged larvae) or after 14 to 15 days (as fully engorged nymphs) were transferred within 4 days to susceptible calves. Three morphologically different A marginale isolates, 1 round (tailless) and 2 with different types of appendages (tailed) were transmitted by the ticks. These findings might explain the overlap of the geographic distribution of the disease and that of Boophilus spp in some areas of the world.

Anaplasma↗
PubMed1992

Defined medium supporting development of cleansed Plasmodium berghei ookinetes in Anopheles stephensi.

Hamsters blood infected with Plasmodium berghei was cultured in vitro for the development of ookinetes. The ookinetes were separated from blood components, suspended in various defined media and fed to Anopheles stephensi through a membrane. The development of the oocysts and infective sporozoites was recorded. Mosquitoes infected with ookinetes suspended in L15 formulated into L15-B, L15-D (a medium specially modified for this purpose), IPL-41 or 199 media with no proteins added, developed at least as many oocysts as the control mosquitoes fed ookinetes suspended in blood. Ookinetes suspended in the L15-B medium yielded more oocysts than after feeding ookinetes suspended in L15-B with 5% casein. Sporozoites from mosquitoes maintained on blood, L15-B, L15-D, or L15-B with 5% casein were shown to be infective to hamsters. Mosquitoes fed ookinetes suspended in sucrose solutions showed very few oocysts, but the yield was increased when a blood meal was given 2-4 days after the infective meal. Some of the oocysts which had developed from the ookinetes suspended in artificial media were found to have degenerated. The described system could be potentially useful for a study of the interaction between the vector physiology and the parasite. The possible use of the system to learn which media should be developed in the future for in vitro cultivation of oocysts is discussed.

Animals↗
PubMed1992

Infectivity of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) to female ticks of Boophilus annulatus (Arachnida: Ixodidae).

Exposing Boophilus annulatus (Say) to different concentrations of Steinernema carpocapsae (Filipjev) infective juveniles in petri dishes (50-10,000 nematodes per dish) resulted in high mortality (greater than 90%) at nematode concentrations as low as 500 nematodes per dish within 8 d. At a concentration of 10,000 nematodes per dish, 100% of the ticks died within 2 d after infestation. After exposure to 500 nematodes per dish, complete mortality was achieved with the Heterorhabditis bacteriophora strain 'HP88' within 4 d. During the same period, only 15 and 40% mortality were recorded with the 'Mexican' and 'All' strains of S. carpocapsae, respectively. In a lethal dose analysis, S. carpocapsae strain 'DT' was the most infective strain with the lowest LD50 and LD90 values (15 and 165 infective juveniles per tick, respectively). The 'All' strain of S. carpocapsae was the least infective of the four strains tested, with LD50 and LD90 values of 372 and 9,251 infective juveniles/tick, respectively. Optimal temperature for tick control by the nematodes was between 22 and 26 degrees C. Mortality rate was reduced at 18 and 30 degrees C. The susceptibility of fully engorged ticks was not influenced by the weight of the replete females. Nematode infection did not have an adverse effect on egg laying by surviving ticks.

Animals↗
PubMed1992

Research note: the hide beetle, Dermestes maculatus DeGeer (Dermestidae), feeds on live turkeys.

The beetle Dermestes maculatus, which is known to feed on dry, protein-rich, stored materials, has lately become a pest of wood and insulating polymers of poultry houses. Its carnivorous attack on live birds is recorded in this paper for the first time. These attacks resulted in deep wounds to adult male turkeys. When beetle larvae were offered simultaneously calf meat, chicken meat, and pellet feed for rodents, no clear preference was noted.

Animals↗
PubMed1991

The effect of defined media, additive nutrients and metabolites on the development of the sporogony cycle of Plasmodium berghei in Anopheles stephensi.

Anopheles stephensi mosquitoes were infected with Plasmodium berghei by feeding on parasitaemic hamsters. After the infective blood meal they were separated into groups that were maintained on sugar solutions containing different additives. The numbers of oocysts developing in the various groups were then compared. When either casein, haemoglobin or foetal bovine serum was added to the sugar, the yield of oocysts was 1.6-2.1 times higher than that in controls fed only on sugar solutions. When either medium 199, Leibovitz's formulated L15 (L15-B) or 'B' compounds alone were added, the yield of oocysts was 2.3-2.9 times higher than that in the controls. The addition of p-aminobenzoic acid, hypoxanthine, methiolnine, or fractions of 'B' had no significant effect on the number of oocysts.

Animals↗
PubMed1990

Development of malaria parasites in mosquitoes fed with ookinetes suspended in defined media.

Information concerning the specific nutritional requirements of malarial parasites developing in the mosquito host has been difficult to obtain, owing primarily to the complex nature of the blood meal that accompanies the parasites and the lack of success in culturing the complete invertebrate cycle of Plasmodium in vitro. The present report describes a blood-free system for infecting mosquitoes with ookinetes of Plasmodium berghei and for allowing the latter to develop into infective sporozoites. Ookinetes cultured in vitro were separated from blood proteins, suspended in defined medium, and fed to Anopheles stephensi mosquitoes through a membrane. The mosquitoes were then maintained on the same defined medium plus 5% sucrose. Infectivity of the parasites was demonstrated 17-19 days later by intracardial inoculation of the macerated mosquitoes into hamsters. This system makes it possible to evaluate nutritional factors that affect parasite development in the mosquito host under controlled conditions.

Animals↗
PubMed1988

Cultivation of Anaplasma marginale from cattle in a Dermacentor cell line.

A tick cell line derived from Dermacentor variabilis (RML-15) was inoculated with bovine RBC infected with Anaplasma marginale. Two hours after inoculation, numerous RBC were phagocytized by the tick cells. After one passage of the cell culture, numerous groups of Anaplasma-like particles were seen in the tick cell cytoplasm. Increased numbers of Anaplasma-like particles also were present. Seemingly, Anaplasma can multiply in tick cells.

Anaplasma↗
PubMed1983

Preparation of suspensions of Hyalomma excavatum ticks infected with Theileria annulata.

Partially engorged adult Hyalomma excavatum ticks infected with Theileria annulata were reared for the preparation of an infective suspension. About 6000 partially engorged infected adults were obtained from 420 non-infective adult ticks. The entire cycle required about 4 months. Six rabbits were used for the production of the fully engorged females. The larvae were fed on 180 gerbils, the nymphs on 17 infected calves and the partially fed adults on 22 goats, 7 sheep and 7 rabbits The adult ticks did not show any host preference.

Animals↗
PubMed1983

Transmission of Theileria annulata (Dschunkowsky & Luhs, 1904) by Hyalomma excavatum (Koch, 1844).

Theileria annulata was transmitted transtadially by an Israeli strain of Hyalomma excavatum from larvae to nymphs and from nymphs to adults. However, the adults developing from larvae which engorged on infected calves and fed during the nymphal stage on non-infected calves, rabbits or gerbils (Meriones tristrami), did not transmit theileriosis. Suspensions of infected unfed nymphs or adults did not produce theileriosis but both nymphs and adults of the same batch became infective to cattle after 2 days of feeding. Suspensions of salivary glands or of whole ticks derived from infected adults that remained attached to rabbits for more than 7 days, were not infective to cattle.

Animals↗
PubMed1982

Relative infectivity of Theileria annulata (Dchunkovsky and Luhs, 1904) stabilates derived from female and male Hyalomma excavatum (Koch, 1844) ticks.

Partially engorged female and male Hyalomma excavatum ticks infected with Theileria annulata were triturated separately in Eagle's minimum essential medium complemented with fetal calf serum. Glycerol was added to the supernatant obtained after centrifugation and the material was frozen at -79 degrees C. Infectivity of the stabilate was titrated by inoculating susceptible calves with dilutions of the material. Stabilate prepared from female ticks was considerably more infective on a per tick basis than stabilate from males. All calves inoculated with an estimated equivalent of 0.1 or more female ticks, or 3.3 or more male ticks, became infected. Time to fever, prepatent period, and mortality did not appear to be dose-dependent in the range of tick equivalents employed.

Animals↗