Forty-four serum samples of various reactivities to rickettsial antigens demonstrated by the indirect immunoperoxidase technique were tested with INDX Dip-S-Ticks (INDX Integrated Diagnostics Inc., USA) Kit for the detection of tick borne diseases. The kit utilised Rickettsia rickettsii the causative agent of Rocky Mountain spotted fever (RMSF) as antigens. The samples positive for endemic typhus were also tested against R. typhi, the agent for endemic typhus by the same method. The aim of this study was to determine the extent of cross-reactivity of R. rickettsii with rickettsial infections in Malaysia. Nine out of 12 tick typhus, 4 out of 10 scrub typhus and 4 out of 12 endemic typhus samples cross reacted with R. rickettsii. Ten out of 12 endemic samples were positive with R. typhi by the same method. From the study, we concluded that the INDX Dip-S-Ticks Kit can be used as a rapid screening test to detect endemic and tick-borne rickettsial infections in Malaysia but a second serological test is strongly recommended on all weakly reactive cases.
Quantitative understanding of the transmission dynamics of lymphatic filarial parasites is essential for the rational planning of control strategies. One of the most important determinants of transmission dynamics is the relationship between parasite yield, the success rate of ingested microfilariae (mf) becoming infective larvae in a mosquito vector, and mf density in the source of the human blood meal. Three types of relationship have been recognized in human filaria/mosquito couples--limitation, facilitation and proportionality; facilitation has hitherto been observed only in the couple Wuchereria bancrofti/Anopheles gambiae in Burkina Faso, in experimental studies on a high density mf carrier. The present paper demonstrates facilitation in W. bancrofti/An. gambiae and W. bancrofti/An. arabiensis in lower mf density carriers in The Gambia and Tanzania, and in W. bancrofti/An. funestus in Tanzania. Facilitation was not found in An. melas in The Gambia nor in An. merus in Tanzania. Analysis of published data shows limitation at low level mf densities in W. bancrofti/Culex quinquefasciatus in Sri Lanka, and in the same couple in India. Limitation also occurs in Brugia malayi/Aedes togoi in experimental cats; proportionality occurs in B. malayi/Mansonia bonneae in Malaysia. The epidemiological significance of these host/parasite relationships is discussed, and supporting evidence for its validity is presented from the published results of large-scale control programmes.
The Helicobacter pylori seroprevalence in a representative population of 328 Melbourne Chinese immigrants (162 men and 166 women) aged 25 years and older were studied. The population consisted of Chinese people born in China/Hong Kong (n = 110, 33.5%), Vietnam (n = 79, 24.1%), Malaysia/Singapore (n = 102, 31.1%), and elsewhere (n = 37, 11.3%). The overall seroprevalence of H. pylori was 59.5%; 60.5% in men and 58.4% in women. Gender specific analysis showed associations between higher seroprevalence and several socio-demographic factors; in men, age (P < 0.0001), lower education level (P < 0.002), cigarette smoking (P < 0.042), the use of antibiotics (P < 0.015) and chopsticks (P < 0.047), and in women, lower socioeconomical status [education level (P < 0.030), gross household income (P < 0.0001) and occupational status (P < 0.0001)] and use of chopsticks (P < 0.002). Seroprevalence differed between immigrants of various birthplaces (P < 0.001); those born in Malaysia/Singapore (43.1%) were lower than those born in China/Hong Kong (68.2%), Vietnam (68.4%), and elsewhere (59.5%). Immigrants of various birthplaces also differed in their pattern of socio-demographics. Multivariate analyses showed that risk factors for H. pylori infection within the Melbourne Chinese immigrants were, in men, age (B = 1.081) and birthplace (B = 1.769) and, in women, household income (B = 0.541) and use of chopsticks (B = 1.654). This study suggests person-to-person transmission of H. pylori via the oral-oral route with ethno-specific food practices an important risk factor.
The relationship among body size (as indicated by wing length), age (as indicated by parity dissections), and malaria infection were observed in host-seeking Anopheles maculatus Theobald females collected in aboriginal villages of peninsular Malaysia. Both ELISA and salivary gland dissections were used to determine malaria infection. The wings of parous females were significantly longer than those of nulliparous females, suggesting that larger females live longer than smaller ones, and thus have a higher vectorial capacity. Body size differences were not detected between infected parous and uninfected parous females. Females infected with only oocysts were significantly larger than females infected with sporozoites. No correlation was found between the number of oocysts or sporozoites and body size in this small sample.
A postal survey of 730 Malaysian dental practitioners was undertaken to assess their awareness and acceptance of the plasma derived hepatitis B vaccine. Only 32% of the 325 practitioners who responded had been vaccinated, 41% intended to be and 15% categorically refused vaccination. The main reservations about vaccine acceptance were fear of side effects including AIDS, cost of the vaccine and lack of information. Vaccine efficacy was not confirmed by serology in two-thirds of the vaccinees and two-fifths of the respondents were unaware that 5% of the vaccinees do not develop a successful antibody response after vaccination. Seventy-eight percent of dentists believed that their risk of contracting hepatitis B was high or very high while 71% recalled having received needle stick injuries in the 3 yr prior to the survey. Only 13% of respondents were aware of delta hepatitis while 63% were aware of non-A non-B hepatitis. The survey has highlighted the need for dissemination of information on hepatitis B vaccine among dentists in Malayasia.
55% of a sample of patients in a rural
community, and 76% of a sample of patients and
staff in the local district hospital were found to
be nasal carriers for Staphylococcus aureus. The
in vitro antibiotic susceptibility patterns of 46
strains of S. aureus isolated in nasal carriers as
well as of 43 strains in community-acquired skin
infections were characterised. High levels of
resistance were expressed to penicillin (73%),
cephalexin (64%) and tetracycline (46%).
Resistance to erythromycin (18%) was moderate.
A few strains showed resistance to methicillin
(5 isolates), vancomycin (4), [usidic acid (3),
cotrimoxazole (1), and none to gentamicin.
Penicillin can no longer be recommended for
treating community-acquired S. aureus infections.
Despite being part of one of the few remaining primitive areas of the world, both Sabah and Sarawak are provided with adequate, though simple, urban and rural general medical services. At present no reliable data on the incidence of sexually transmitted diseases in these areas have been collected and no organised treatment services are available. Gonorrhoea appears to be the commonest notifiable infectious disease in Sarawak, and beta-lactamase-producing strains have been isolated. Because of the rapidly expanding economy and the encouragement of the tourist trade, sexually transmitted disease is likely to prove an increasing problem, for which a specialised service for diagnosis and treatment is badly needed.
First six cases of neonatal group B beta-haemolytic streptococcal sepsis in GHKL & Maternity Hospital K.L. were reported and in one third, it was fatal. Five of the cases were 'early - onset' type and one was 'late - onset' type. While maternal infant transmission of the disease is important in the 'early - onset' type, environmental sources of infection are also significant. No gestational age or birthweight is spared from the disease. Finally, there are cases of 'early - onset' GBS sepsis presenting like hyaline membrane disease of the newborn and it is important to find ways to distinguish them which so far has not been satisfactory.
Schistosomiasis was discovered in Malaysia in 1975 in an autopsy case. Since 1975 autopsies, surveys, and resurveys have been carried out to identify animal hosts, snail intermediate hosts, and reservoir hosts. Seroepidemiologic tests involving enzyme-linked immunosorbent and circumoval precipitin methods have been used to determine the true incidence and prevalence of this protean disease among the Orang Aslis (aborigines) in Malaysia. With the use of better epidemiologic and parasitologic tools, more cases of schistosomiasis are being reported.
A survey of 4.112 primary school children living in and around Kuala Lumpur, Malaysia, revealed that 12.9% of the children were infested with Pediculus humanus capitis. Indians (28.3%) and Malays (18.9%) have a higher prevalence than Chinese (4.6%). The higher prevalence among Indians and Malays correlates well with their lower socio-economic status in the community; long hair also contributes to the higher rates of pediculosis among them. The prevalence rate was found to be related to socio-economic status, length of hair, family size, age, crowding and personal hygiene. Treatment with 0.2% and 0.5% malathion in coconut oil gave cure rates of 93% and 100%. Treatment with gammexane and actellic at 0.5% concentration gave a cure rate of 100% against adults and nymphs of Pediculus humanus capitis.
A survey of 25,246 Malay, Chinese and Indian children and adults ranging from birth to over 60 years of age, of both sexes, from 4 types of communities with different conditions of environmental sanitation and socio-economic status revealed an overall incidence of infection with soil-transmitted helminths of 39.6 percent. The incidence of soil-transmitted helminthiasis was highest among rural rubber estates, followed closely by the urban slums or squatter areas and incidence of infection was low in the semi-rural new villages and the urban flats. The commonest helminth in all these areas was Trichuris trichiura and the commonest type of helminthic infection was mixed infections with Ascaris and Trichuris. Infection was most prevalent among Indians, followed closely by Malays. Chinese generally had lower incidences of infection. Soil-transmitted helminthiasis was also more prevalent among the younger age groups, starting from toddlers to 9 years and rising to a peak in the 10-19 years age group. Elderly people (60 years and above) from the squatter areas and some ofthe estates, new villages andflats also had a higher incidence of infection than the older adults (30-59 years). Malay and Indian children (under 15 years of age) having a higher overall incidence of injection also tended to have higher degrees of infection, as estimated by egg counts. There was no significant differences in the distribution of infection between males and females in most of the study areas. However, females in the squatter areas had a higher incidence of infection than males. Conversely, females in some of the flats (Sri Melati and Shaw Road) had a lower incidence of infection than males.
HBeAg and anti-HBe were determined in the blood of 189 male blood donors. The incidence of HBsAg was 6.9% while that for HBeAg and anti-HBe was 1.6 and 18%, respectively. Of the 13 samples positive for HBsAg, two (15.4%) were positive for HBe while six (46.2%) were positive for anti-HBe. One specimen was negative for HBsAg but was positive for HBeAg and anti-HBe. The observations are discussed.
During the intermonsoon period from mid-September to mid-October 1986, wild-caught Anopheles balabacensis Baisas females were marked and released in a host-choice experiment. Association between capture and recapture of marked mosquitoes from human and bovid hosts and blood meal host identification of recaptured females were determined on a daily basis. Although the mark-recapture and blood meal data indicated behavioral heterogeneity between buffalo and human biters, restriction endonuclease fragment length polymorphism analysis revealed no differences in repeat sequence profiles. Doubly-marked recaptures strongly indicated a "learning" component involved in a separate host preference experiment. In a "habitat loyalty" experiment conducted in January 1987, females of An. balabacensis preferentially returned to the resting sites (indoor surfaces and exit traps) where they were first caught. Of nine isozyme loci found to be polymorphic, the genotypic frequencies of Esterase-3 and Isocitrate dehydrogenase-3 were different in "faithfully" endophilic and exophilic subpopulations. Genetic heterozygosity, as determined by polyacrylamide gel electrophoresis, was greater in exophilic than endophilic population components. These results confirm that genetic and learning components can significantly influence house resting and host seeking behavior and may contribute to local epidemiological patterns of malaria transmission observed in Sabah, Malaysia.
Holoendemic malaria transmission in two small isolated forest communities and a coastal village was studied by (1) all night human bait collections of Anopheles species from inside and outside houses and (2) buffalo-biting and CDC light-trapping catches during March and November 1984. During the same period thick and thin blood films were collected from the human population, and spleen rates were determined in children from two to nine years of age. Using both the immunoradiometric assay (IRMA) and the dissection technique, more sporozoite-positive infections were detected in An. balabacensis and An. flavirostris in November than in March. IRMA confirmed the presence of Plasmodium falciparum sporozoites. An average of 76.2% of the An. balabacensis population lived long enough to have reached a point where infectivity with P. falciparum was possible in November. Although fewer than five adult females bit humans per night at any time, a resident could theoretically have received more than 160 infective bites in one year. A high frequency of feeding on humans, coupled with increased anopheline life expectancy, contributed to high estimates of falciparum malaria vectorial capacity (number of infections distributed per case per day); for An. balabacensis (1.44-7.44 in March and 9.97-19.7 in November) and for An. flavirostris (0.19-5.14 in March and 6.27-15.8 in November). These high values may explain the increased malaria parasite rates obtained from at least two forest communities. Correlation between actual and calculated rates of gametocytaemia was poorest in Kapitangan due to inadequate sampling of the human population. In Banggi island, malaria is stable and holoendemic, and the population enjoys a high degree of immunity.
Haemorrhagic fever with renal syndrome (HFRS) is caused by a group of RNA viruses within the family of Bunyaviridae known as hantaviruses. The classical, severe form of HFRS is characterized by fever, headache, abdominal and lumbar pain, proteinuria, haemorrhagic phenomena, shock and renal failure. The disease is associated with the prototype Hantaan virus and occurs in rural areas of Korea and China with Apodemus mice as reservoir hosts. A clinically less severe form of HFRS, which is caused by Seoul virus, occurs in urban areas with the house rat Rattus novegicus as the main reservoir host. The disease in nonendemic areas may be atypical and patients with symptoms the hepatitis and minimal renal involvement have been observed in Malaysia. Outbreaks of HFRS in humans involving infected laboratory rat colonies have occurred in several medical centres in various countries. Hantaviruses cause a chronic, asymptomatic infection in rodents which excrete the virus in their lungs, saliva and urine. Man becomes infected mainly by inhalation of infected droplets from healthy rodent carriers. Seroepidemiological studies using mainly the indirect immunoflourescent antibody test of sera from humans and rats showed that hantaviruses have a worldwide distribution.
Matched MeSH terms: Hemorrhagic Fever with Renal Syndrome/transmission*
A questionnaire was mailed to 1217 dentists whose names appear in the Dentist Register of 1987 in order to assess their awareness and acceptance of hepatitis B vaccine and their pattern of glove usage. Almost all the respondents (99.6%) were aware of the availability of the hepatitis B vaccine yet only 44.8% have received the vaccine. This is in spite of the fact that the majority (61.2%) of the vaccine non-acceptors have no reservations concerning the vaccine. About 71% and 63% of the vaccine-acceptors and non-acceptors respectively believed that the risk of their contracting hepatitis B was high or very high. About 22% of the vaccine non-acceptors never used gloves when treating patients as compared to 9% among vaccine acceptors. Overall, about 78% of the respondents have experienced needleprick injuries in the 3 years preceding the survey.