Infectious and tropical diseases in Oman: a review.

Oman is generally hot and dry, but the Salalah region in southern Dhofar province is relatively cool and rainy during the summer monsoon, and has a distinctive pattern of infection. Important, notifiable infections in Oman include tuberculosis, brucellosis (endemic in Dhofar), acute gastroenteritis, and viral hepatitis: 4.9% of the adults are seropositive for hepatitis B surface antigen and approximately 1.2% for hepatitis C virus. Infection with human immunodeficiency virus is uncommon, and leprosy, rabies, and Crimean-Congo hemorrhagic fever are rare. Between 1990 and 1998, the incidence of malaria, (>70% due to Plasmodium falciparum) decreased from 32,700 to 882 cases. Cutaneous and visceral leishmaniasis (caused by Leishmania tropica and L. infantum, respectively) and Bancroftian filariasis occur sporadically. Intestinal parasitism ranges from 17% to 42% in different populations. A solitary focus of schistosomiasis mansoni in Dhofar has been eradicated. There are major programs for the elimination of tuberculosis, leprosy, and malaria, and to control brucellosis, leishmaniasis, sexually transmitted diseases, trachoma, acute respiratory infection in children, and diarrheal diseases. The Expanded Program on Immunization was introduced in 1981: diphtheria, neonatal tetanus, and probably poliomyelitis have been eliminated.

Smokeless tobacco use in Sri Lanka.

UNLABELLED: To comprehensively review the issues of smokeless tobacco use in Sri Lanka . This review paper is based on a variety of sources including Medline, WHO documents, Ministry of Health and Nutrition, Colombo and from other sources. RESULTS: The prevalence of smokeless tobacco (SLT) use in Sri Lanka has been reported high, especially among rural and disadvantaged groups. Different smokeless tobacco products were not only widely available but also very affordable. An increasing popularity of SLT use among the youth and adolescents is a cause for concern in Sri Lanka. There were evidences of diverse benign, premalignant, and malignant oral diseases due to smokeless tobacco use in the country. The level of awareness about health risks related to the consumption of smokeless tobacco products was low, particularly among the people with low socio-economic status. In Sri Lanka various forms of smokeless tobacco products, some of them imported, are used. At the national level, 15.8% used smokeless tobacco products and its use is three-fold higher among men compared to women. Betel quid is by far the traditional form in which tobacco is a general component. Other manufactured tobacco products include pan parag/pan masala, Mawa, Red tooth powder, Khaini, tobacco powder, and Zarda. Some 8.6% of the youth are current users of smokeless tobacco. There are studies demonstrating the harmful effects of smokeless tobacco use, especially on the oral mucosa, however, the level of awareness of this aspect is low. The highest mean expenditure on betel quid alone in rural areas for those earning Rs. 5,000/month was Rs. 952. The core issue is the easy availability of these products. To combat the smokeless tobacco problem, public health programs need to be intensified and targeted to vulnerable younger age groups. Another vital approach should be to levy higher taxation.

Poliomyelitis in Oman: acute flaccid paralysis surveillance leading to early detection and rapid response to a type 3 outbreak.

Countries are increasingly requesting guidance on carrying out acute flaccid paralysis (AFP) surveillance, aimed at detecting and confirming all cases of acute paralytic poliomyelitis. The experience of Oman provides many lessons in this respect. AFP surveillance in Oman was established systematically. First, an epidemiologist was assigned to coordinate surveillance, and a laboratory for performing polio-virus isolation was identified. Next, operational guidelines for AFP surveillance were developed and widely promoted among health staff. The quality of the system has been monitored for more than 3 years with selected performance indicators. From January 1990 to April 1993, 49 AFP cases were reported, corresponding to an average annual rate of 2.1 AFP cases per 100,000 children aged less than 15 years. A total of 98% of the AFP cases were investigated within 48 hours of being reported; two stool samples were obtained from 94% of the cases. Following complete investigation, nearly a third of the reported AFP cases were classified as being clinically compatible with Guillain-Barré syndrome. Four AFP cases, all reported in 1991, were confirmed to be due to wild type 3 poliovirus. Because AFP surveillance detected these cases rapidly, Oman was able to carry out outbreak control measures promptly and more than 350,000 extra doses of oral poliovirus vaccine were delivered to children under 6 years of age.

Sequential use of inactivated poliovirus vaccine followed by oral poliovirus vaccine in Oman.

Seroprevalence and geometric mean titers (GMTs) were compared at 6 and 10 months after vaccination with monovalent type 1 oral poliovirus vaccine (OPV) at 6 months and trivalent OPV at 7 and 9 months. Group 1 had received 4 doses of OPV, group 2 OPV at birth and 3 doses of OPV and inactivated poliovirus vaccine (IPV), and group 3 placebo at birth and 3 doses of IPV. A total of 547 infants completed the study. At 10 months, seroprevalence to poliovirus type 1 was 98%, 99%, and 98% in groups 1, 2, and 3; 100%, 100%, and 98% to poliovirus type 2; and 80%, 96%, and 91% to poliovirus type 3. Differences in seroprevalence among the groups were significant for poliovirus type 3 (P < .001). Between 6 and 10 months, significant increases in seroprevalence and GMTs occurred for poliovirus type 1 but not for types 2 and 3. Two OPV doses following 3 IPV doses did not significantly increase seroprevalence or raise GMTs for poliovirus types 2 and 3; however, significant increases were found for poliovirus type 1, which may have benefitted from monovalent type 1 administration.

Crimean-congo haemorrhagic fever: a seroepidemiological and tick survey in the Sultanate of Oman.

In 1995 and 1996, 4 persons from the Sultanate of Oman were confirmed with clinical Crimean-Congo haemorrhagic fever (CCHF). To assess the prevalence of CCHF virus infection in Oman, a convenience sample of imported and domestic animals from farms, abattoirs and livestock markets was examined by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to CCHF virus. Ticks were collected from selected animals, identified, pooled by species, host and location and tested for evidence of infection with CCHF virus by antigen-capture ELISA. Serum samples from individuals working in animal and nonanimal contact-related jobs were also tested for CCHF antibodies. Serological evidence of infection was noted in 108 (22%) of 489 animals. Most of the ticks collected (618 of 912) from all species of sampled livestock were Hyalomma anatolicum anatolicum, a competent vector and reservoir of CCHF virus. 243 tick pools were tested for CCHF antigen, and 19 pools were positive. Of the individuals working in animal contact-related jobs, 73 (30.3%) of 241 non-Omani citizens and only 1 (2.4%) of 41 Omani citizens were CCHF antibody-positive. Butchers were more likely to have CCHF antibody than persons in other job categories. The presence of clinical disease and the serological results for animals and humans and infected Hyalomma ticks provide ample evidence of the presence of CCHF virus in yet another country in the Arabian Peninsula.