The effect of relative humidity (RH) and temperature on the survival of airborne bovine rotavirus UK isolate (BRV-UK) and a murine rotavirus (MRV) was studied. In any one experiment, the virus under test was suspended in tryptose phosphate broth (TPB) supplemented with uranine (physical tracer) and an antifoam, was aerosolized using a Collison nebulizer into the rotating drum with the RH at either low (30 +/- 5%), medium (50 + 5%) or high (80 +/- 5%) level at 20 +/- 1 degrees C. Following a 15-min period of viral aerosol stabilization, sequential samples of drum air were collected using an All-Glass Impinger (AGI) for 24 h post-aerosolization. Both of the rotavirus isolates were found to survive best at medium RH level and high RH was found least favorable for the survival of these aerosolized rotaviruses. The survival pattern of aerosolized MRV was found to be the best when compared with survival pattern of all animal and human rotavirus isolates studies performed under aerosolized conditions in our laboratory. The findings of these experiments confirm and extend our previous reports on the survival of other animal and human aerosolized rotaviruses and emphasize the fact that air may be one of the vehicles for their dissemination and could explain why it is difficult to control nosocomial outbreaks of rotavirus gastroenteritis and to keep animal colonies rotavirus-free.

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A concerted malaria eradication programme in the United Arab Emirates has reduced local transmission to only a very few small foci in the country. The Al Ain district is now a consolidation zone. However, transmission across the undemarcated border with Oman continues. Malaria imported by the large immigrant work force from major disease endemic areas remains a large burden. An added threat is the appearance of chloroquine-resistant Plasmodium falciparum principally from Sudan and Pakistan but increasingly amongst Omani cases seen in the hospitals and clinics in Al Ain. The implications of re-introduction of malaria and the establishment of chloroquine resistance, particularly for non-immune residents and visitors, are emphasized.

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Of 246 people living in Kuwait and selected at random, 95.5% gave a positive reaction to the indirect haemagglutination test for antibodies to Toxoplasma gondii, of whom approximately 34% had medium to high titres (1:128 to 1:4096). There was no obvious difference between the proportion of females and males who had been infected. Approximately double the proportion of people in the age groups 20 to 31 and 32 to 43 years had medium to high titres compared with those in other age groups. Even between the former two groups, the percentage with the highest titres (1:512 to 1:4096) declined with age; none was found in the oldest group. When analysed in terms of nationalities, the pattern of results obtained with a small group of Bedouins, where most had medium to high titres, was the opposite of that found with urban Kuwaitis and people of other nationalities. It is suggested that the Bedouins may be particularly prone to the infection.

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Alveolar hydatid cysts (AHC) were isolated from C57BL/6J and BALB/c mice at 8 and 12 weeks post-infection from subcutaneous and intraperitoneal foci and cultured in vitro. Freshly isolated as well as in vitro-grown cysts were incubated with Fc or F(ab')2 fragments of human, rabbit, mouse, goat or sheep immunoglobulins, then washed and incubated with a fluorescein-conjugated rabbit or goat F(ab')2 fraction of antisera to each of the above primary sera. Significant fluorescence on the surface of AHC was detected when they were incubated with human, rabbit or mouse Fc fractions followed by the addition of goat or rabbit fluorescein-conjugated antiserum. No fluorescence was detected when the AHC were incubated with the F(ab')2 fragments and fluorescein-conjugated antiserum, except when the primary antiserum was mouse F(ab')2 fractions. Cysts grown in vitro retained their binding ability to human, rabbit or mouse Fc fractions. However, the intensity of fluorescence decreased proportionally with time. The maximum intensity of staining was observed with small cysts. Large cysts showed diminished fluorescence. The non-specific binding of human, mouse or rabbit immunoglobulins (Fc fractions) to AHC was also confirmed by rosetting with sheep erythrocytes (SRBC) which suggests that the larvae of Echinococcus multilocularis may utilize the presence of Fc receptors on their surface in order to elude immune destruction by the host.