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Biomedical subjects

R B Tesh

Publications and source records attributed to R B Tesh.

At least 127 records · Page 7Linked to original sources
PubMed1983

Transovarial transmission of dengue viruses by mosquitoes: Aedes albopictus and Aedes aegypti.

Transovarial transmission of all four dengue serotypes was demonstrated in Aedes albopictus mosquitoes. The rates of such transmission varied with the serotype and strain of virus. In general, the highest rates were observed with strains of dengue type 1 and the lowest with dengue type 3. Surprisingly, despite the use of viral strains of the four dengue serotypes which gave the highest rates with Ae. albopictus, transovarial transmission was observed in Aedes aegypti only with dengue type 1, and then only at a relatively low rate. Five different strains of Ae. aegypti were employed, including one that was known to be relatively susceptible to oral infection with dengue viruses. The findings support the view that Ae. aegypti, while of major importance from the point of view of transmission of dengue to man, may be relatively unimportant in the overall natural history of dengue viruses.

Aedes↗
PubMed1983

Characterization of eight new phlebotomus fever serogroup arboviruses (Bunyaviridae: Phlebovirus) from the Amazon region of Brazil.

Eight new members of the phlebotomus fever arbovirus serogroup (family Bunyaviridae; genus Phlebovirus) from the Amazon region of Brazil are described. One serotype was recovered from a febrile patient, three from small wild animals and four from sand flies. A small serum survey carried out with the human isolate, Alenquer virus, suggests that it rarely infects man. Complement-fixation and plaque reduction neutralization tests were done, comparing the eight new viruses with other members of the phlebotomus fever serogroup. A close antigenic relationship was demonstrated between one of the new agents (Belterra) and Rift Valley fever virus. This finding is of considerable interest and deserves further investigation. Addition of these eight new viruses to the genus Phlebovirus brings to 14 the number of serotypes known to occur in the Amazon region and to 36 the total number reported worldwide. More detailed clinical and epidemiological studies should be conducted in Amazonia in order to define the public health impact caused by phleboviruses.

Animals↗
PubMed1983

Detection of promastigote stage-specific antigens on Leishmania mexicana amazonensis developing in the midgut of Lutzomyia longipalpis.

Previously described monoclonal antibodies IX-IF9-D8, IX-2H7-E10 and IX-5H9-C1 recognize promastigote stage-specific determinants present on externally exposed membrane proteins of axenically cultured Leishmania mexicana amazonensis. In the present study, these antigens were demonstrated by indirect immunofluorescence to be present on promastigotes found in the gut lumen of infected Lutzoymia longipalpis. The presence of these antigens on promastigotes found in infected sandflies suggests that the same antigens should be relevant for protective immunity studies and for species identification of Leishmania encountered in epidemiological studies.

Animals↗
PubMed1983

Growth and transovarial transmission of Chandipura virus (Rhabdoviridae: Vesiculovirus) in phlebotomus papatasi.

Chandipura virus multipled in sand flies (Phlebotomus papatasi) following intrathoracic inoculation. Within 24 hours, mean virus titers in infected flies increased approximately 4 logs. Experimentally infected P. papatasi transmitted the virus by bite to newborn mice and by transovarial transmission to their progeny. Eight percent of the F1 offspring of experimentally infected female parents were infected with Chandipura virus.

Animals↗
PubMed1983

Transovarial transmission of Rio Grande virus (Bunyaviridae: Phlebovirus) by the sand fly, Lutzomyia anthophora.

The growth of Rio Grande (RG) virus, the only phlebovirus known to occur in the United States, was studied in Lutzomyia anthophora, its suspected sand fly vector. RG viral titers in infected flies increased more than 10,000-fold within 7 days after intrathoracic inoculation. Experimentally infected female L. anthophora transmitted virus transovarially (vertically) to 54.8% of their F1 progeny. This is the first virologically confirmed demonstration of transovarial transmission of a phlebovirus by sand flies. It indicates one mechanism by which RG and possibly other phleboviruses may be maintained in nature.

Bunyaviridae↗
PubMed1982

Arthritides caused by mosquito-borne viruses.

Five different mosquito-borne viruses (chikungunya, o'nyong-nyong, Mayaro, Ross River, and Sindbis) have been associated with arthritis in humans. These agents occur most commonly in the tropics and subtropics. The symptoms they produce are similar and typically consist of fever, arthralgia, and rash. In general, the symptoms are of short duration (less than one week) and recovery is complete, although some patients have recurrent episodes of joint swelling and tenderness for months after infection. Treatment is symptomatic. There are no vaccines currently available; the best prevention is to avoid mosquito bites when traveling or living in areas where these diseases occur.

Arbovirus Infections↗
PubMed1981

Ross River virus (Togaviridae: Alphavirus) infection (epidemic polyarthritis) in American Samoa.

An outbreak of Ross River virus infection (epidemic polyarthritis), which occurred in American Samoa between August 1979 and January 1980, is described. On the basis of a serological survey performed near the end of the epidemic, it is estimated that at least 13,500 people were infected. Ross River virus was isolated from the blood of a single polyarthritis patient. Plaque reduction neutralization tests, using this virus strain, were done on 393 human and 143 animal sera collected on Tutuila island. Over-all, 43.8% of the people sampled had evidence of infection. Sera from 100 adult residents of the same island, collected in 1972, had no Ross River antibody, suggesting recent introduction of the virus. In contrast to the human serological data, the prevalence of Ross River antibodies among animals was relatively low. Dogs and pigs had the highest rates with 20% and 15%, respectively. Results of this study suggest that the Ross River virus cycle during the epidemic in American Samoa involved primarily humans and mosquitoes with animals less frequently infected. These observations plus the recent introduction of Ross River virus into new areas of the South Pacific suggest that a major change has occurred in the epidemiology of epidemic polyarthritis.

Adolescent↗
PubMed1981

The location of San Angelo virus in developing ovaries of transovarially infected Aedes albopictus mosquitoes as revealed by fluorescent antibody technique.

Aedes albopictus adult female mosquitoes, transovarially infected with San Angelo (SA) virus, were examined by fluorescent antibody technique during various stages of ovarian development to determine how the virus enters the egg. Upon emergence from the day of adulthood, it was visible in the follicular epithelium, oocytes and nurse cells of the primary follicles. In the 72-hour period between the ingestion of blood and oviposition, there was a marked increase in the amount of viral antigen in the oocyte, indicating rapid virus accumulation. After oviposition, SA viral antigen was also seen in the secondary ovarian follicles. The observed sequence of infection of the mosquito ovariole with SA virus is analogous to that described with certain endosymbionts of insects.

Aedes↗
PubMed1980

Transovarial transmission of yellow fever virus in Stegomyia mosquitoes.

Transovarial transmission of two strains of yellow fever virus was demonstrated in three colonized geographical strains of Aedes aegypti following infection by intrathoracic inoculation. Infected progeny were detected in F1 offspring from only the first three ovarian cycles (OVC). The overall minimum filial infection rate for the first three OVC was 1:596; rates were loser in the second and third OVC. Virus survived in eggs for longer than 4 months and was recovered from progeny of three immersions of first OVC eggs. Infected progeny averaged a longer time to pupation than noninfected siblings. Transovarial transmission of virus was also demonstrated in first OVC progeny of Aedes mascarensis.

Aedes↗
PubMed1980

The mechanism of arbovirus transovarial transmission in mosquitoes: San Angelo virus in Aedes albopictùs.

The mechanism of transovarial transmission of San Angelo (SA) virus in Aedes albopictus was investigated.A mosquito line with SA virus filial infection rates of almost 100% was developed by selection. Results of crosses and back-crosses between this transovarial transmission-efficient line and noninfected mosquitoes indicated that SA virus was transmitted in Ae. albopictus by maternal inheritance. The infection status of the male parent was of no consequence; the virus was passed from generation to generation through the females. Transovarially infected mosquitoes contained less virus than insects infected by inoculation. The behavior of SA virus in Ae. albopictus was similar to that of sigma virus in Drosophila melanogaster, suggesting that some females in the transovarial transmission-efficient line had developed a chronic infection of their germinal cells (oogonia). Serial transovarial passage of SA virus in Ae. albopictus did not alter its plaque morphology, infectivity for mosquitoes, or pathogenicity for vertebrates. Transovarially infected mosquitoes transmitted the virus by bite to mice.

Aedes↗
PubMed1979

A method for the isolation and identification of dengue viruses, using mosquito cell cultures.

An improved method for the isolation and identification of dengue viruses is described. Viruses were isolated in mosquito cell cultures (C6/36 or AP-61), identified by indirect fluorescent antibody technique, and typed by complement-fixation test, using the cell culture fluid as antigen. The sensitivity of this method was compared with mosquito inoculation in comparative titrations of 16 low passage dengue virus strains. Although lower virus titers were obtained by the mosquito cell culture technique, its decreased sensitivity was compensated for by the much larger volume (588X) which could be assayed. By incubating the mosquito cells at 32 degrees C, dengue viruses can be identified and typed within 6 days after inoculation.

Animals↗