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R Traub

Publications and source records attributed to R Traub.

At least 55 records · Page 3Linked to original sources
PubMed1968

Ecological considerations in scrub typhus. 3. Methods of area control.

The best of the known methods for control of the chigger vectors of scrub typhus is the application of dieldrin to the ground and low-lying vegetation as a fog or spray at the rate of 2.5 lb to the acre (28 kg/hectare). This has produced a more than 91% reduction in the numbers of Leptotrombidium (L.) akamushi (Brumpt, 1910) and L. (L.) deliense (Walch, 1922) for at least 2 years. Aldrin applied at the rate of 2.25 lb per acre (2.5 kg/hectare) is also highly effective, but less so than dieldrin. Lindane at the rate of about 5 lb per acre (5.7 kg/hectare) ranks third, but offers protection for only about 2 months. Because of the potential hazards to wildlife when such long-acting compounds are used, application of organophosphorous or carbamate insecticides may be used instead in areas where reapplication every few weeks is feasible. Fenthion and arprocarb are promising compounds for this purpose.

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PubMed1968

Ecological considerations in scrub typhus. 1. Emerging concepts.

Scrub typhus infection is now known to occur in geographical and ecological areas where its presence was hitherto unsuspected-north and west of the Indus River and in south-eastern Siberia; in semi-desert, montane desert, and alpine terrain high in the Himalayas, as well as in primary jungle. Additional data are presented to support the hypothesis that "ecological islands", containing basically similar faunas of rodents and ectoparasites, exist on scattered mountains in the Pakistan Himalayas, despite the intervening "barriers" of desert, broad rivers and massive peaks. Since scrub typhus has been demonstrated in some of these isolated areas, it is felt that the infection may exist, unrecognized, in neighbouring countries as well.A number of larval trombiculid mites, largely species of the subgenus Leptotrombidium, are believed to be vectors, in addition to the well-known L. (L.) deliense and L. (L.) akamushi. The host-range of natural infection in ground-dwelling small mammals, especially rodents, is very broad in endemic areas. An important factor of time, and not only of space, may be involved in an endemic locus, the disease undergoing a sequential evolution involving different chiggers and rodents over a period of years. It is pointed out that new irrigation schemes, road construction, and agricultural projects may introduce scrub typhus into an area or greatly increase its endemicity if the infection is already present.

Animals↗
PubMed1968

Ecological considerations in scrub typhus. 2. Vector species.

Certain features, characteristic of outbreaks of scrub typhus, can be explained by the behaviour of the chigger vectors which are remarkably hardy and can survive weeks of freezing or immersion in water. The established vectors are all species of the genus Leptotrombidium (Leptotrombidium), i.e., L. (L.) akamushi (Brumpt, 1910), L. (L.) deliense (Walch, 1922), L. (L.) pallidum (Nagayo et al., 1919), and L. (L.) scutellare (Nagayo et al., 1921). These chiggers (i.e. larval mites) infest a broad variety of birds and mammals, and tend to be found in clusters on certain specific sites on the host. However, the precise site for any species of mite varies with the host, and it is believed that the grooming habits of the infested animal account for this "site preference". The degree of infestation cannot validly be ascribed to the size of the host. L. (L.) pavlovskyi (Schluger, 1948), L. (L.) orientale (Schluger, 1948), L. (L.) arenicola Traub, 1960, and L. (L.) tosa (Sasa & Kowashima, 1951) are regarded as probable vectors. Other species, some belonging to other genera, are under suspicion in this regard.L. (L.) subintermedium (Jameson & Toshioka, 1954) and certain other chiggers were found in "ecological islands" in all montane habitats studied in West Pakistan, despite the intervening high mountains, broad rivers and belts of semi-desert. The infection-rate of Rickettsia tsutsugamushi in vector species in nature is believed to be low, and chiggers may be serving as reservoirs of infection and not just as vectors.

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