The gastrointestinal helminth infection status of 1574 children living in a slum area of Kuala Lumpur, Malaysia was assessed by quantitative coprology. Almost two-thirds were infected with Trichuris trichiura, 49.6% with Ascaris lumbricoides, and 5.3% with hookworm. Infection prevalence rose rapidly to a stable asymptote at 7 years of age, and the age-intensity profile was convex with maximal values in the 5-10 year age classes. This pattern was the same for males and females, but differed markedly between different ethnic groups. The frequency distributions of A. lumbricoides and T. trichiura were highly overdispersed (k values were 0.21 and 0.27, respectively), and age-dependent over the 0-8 year age classes. This suggests that the force of infection with these nematodes is lower in infants than in older children.
A survey was conducted in 4 paediatric wards in Malaysia to determine the distribution of various species of cockroaches and to examine their gut contents for bacteria. Cockroaches were trapped from food dispensing areas (kitchens), store rooms, cupboards and open wards. 104 cockroaches were caught, consisting of Periplaneta americana (67.3%), Blattella germanica (26%), P. brunnea (4.8%), and Supella longipalpa (1.9%). Bacteria were isolated from all cockroaches except 3 P. americana. Many bacterial species were identified, including the pathogenic and potentially pathogenic species Shigella boydii, S. dysenteriae, Salmonella typhimurium, Klebseilla oxytoca, K. ozaena and Serratia marcescens.
Ovalocytosis, an hereditary condition in which most erythrocytes are oval in shape, is a polymorphism that occurs in up to 20% or more of the population in Papua New Guinea and Malaysia. Due to the geographical correlation of the trait with endemic malaria, the possibility of a selective advantage in resistance to malaria has been raised. In a study of 202 individuals with greater than or equal to 50% oval red cells matched by age, sex and village of residence with controls having less than or equal to 30% oval cells, ovalocytic subjects had blood films negative for Plasmodium vivax (P = 0.009), for P. falciparum (P = 0.044), and for all species of malaria parasites (P = 0.013), more often than controls. Among individuals parasitaemic at any time there were no clear differences in density of parasitaemia. However, in children 2 to 4 years old, parasite densities of both species were lower in ovalocytic subjects than in controls (0.01 less than P less than 0.025). The differential susceptibility to malaria infection suggested by this study has implications for the evaluation of interventions, including possible future vaccine field trials, in populations where high-frequency ovalocytosis is present.
Plasmodium falciparum drug sensitivities to chloroquine and mefloquine were assessed with WHO in vitro microtechnique test kits in 5 localities near the border with Thailand in Peninsular Malaysia. 105 of 113 (92.9%) parasite isolates were successfully tested and 103 (98.1%) showed resistance to chloroquine with parasite growth even at greater than or equal to 5.7 pmol of the drug. All these isolates were sensitive to mefloquine, parasite growth being inhibited at less than or equal to 11.3 pmol of the drug.
A serological study on dengue infection conducted in Singapore during the period 1982 to 1984 showed that 54.4% of the healthy population between 6 months and over 50 years of age surveyed possessed no haemagglutination-inhibition antibody to dengue type 2 virus. Children below 10 years of age showed the lowest antibody prevalence and were at the greatest risk, with 96.6% susceptible to infection, whereas virtually all adults over 40 showed evidence of prior dengue infection. The geometric mean titre showed a rising trend indicating continuing acquisition of infection in the older age groups. The seropositivity rate of dengue infection of males was twice that of females. Among the 3 major ethnic groups, no significant difference in seropositivity was noted between the Malays and Indians, but the differences between Malays and Chinese and between Indians and Chinese were statistically significant. The study confirmed that the successful implementation of the nation-wide Aedes control programme is reducing endemic dengue virus transmission in the country.
During the early months of 1985 and 1986, 408 non-immune British soldiers undertook training in the jungles north of Kota Tinggi, in southern Malaysia. In this geographical location, where malaria transmission is now light, a combination of strict personal antimosquito measures plus proguanil 200 mg daily produced effective, safe protection, with only a single case of vivax malaria occurring. Given the limited malaria risk, however, the results of this study should be extrapolated only with caution to other areas of Malaysia.
In 1977 and 1978 selected in-patients at the Tegalyoso Hospital, Klaten, Indonesia who had recent onsets of acute fever were serologically studied for evidence for alphavirus and flavivirus infections. A brief clinical history was taken and a check list of signs and symptoms was completed on admission. Acute and convalescent phase sera from 30 patients who showed evidence that a flavivirus had caused their illnesses were tested for neutralizing antibodies to several flaviviruses which occur in South-east Asia. Paired sera from seven patients demonstrated a fourfold rise in antibody titre from acute to convalescent phase. The most common clinical manifestations observed in this series of patients included high fever, malaise, stomach ache, dizziness and anorexia. None of the seven patients had headache or rash despite the fact that headache and rash had been associated with two of the three previously studied. The onsets of illness clustered toward the end of the rainy season when populations of Aedes aegypti, a probable vector in Malaysia, were most abundant.
A case of Plasmodium falciparum malaria resistant to Fansidar (sulphadoxine plus pyrimethamine) at a level corresponding to R III and resistant to chloroquine is reported. The infection was most certainly acquired in Malaysia, but diagnosed and treated in a non-malarious area. Normal resorption and elimination rates of the Fansidar components excludes cure failure due to abnormal drug fate in the host. P. falciparum parasites from the patient have been maintained in vitro cultures. The patient was permanently cured with mefloquine.
Doxycycline in a single dose was found to be a valuable drug in the treatment of chloroquine-resistant falciparum malaria. It was less effective in a single daily dose of 4 mg/kg body-weight for four days, when it cured only five out of nine patients, while a dosage of 4 mg/kg body-weight for seven days cured 23 out of 26 patients.
Enteritis necroticans (EN), known as pigbel in Papua New Guinea (PNG), may be the important predisposing lesion to mid-gut volvulus, jejunal and ileal ileus and other forms of small bowel strangulation in communities where protein deprivation, poor food hygiene, epochal meat feasting and staple diets containing trypsin inhibitors co-exist. Such human habitats occur in Africa, Central and South America, western Pacific, Asian and south-east Asian cultures. Isolated outbreaks of necrotizing enteritis have been reported from Uganda, Malaysia and Indonesia but as yet no systematic epidemiological study of the prevalence of small bowel strangulations has been described in the surgical literature of 'third world' countries. Now that enteritis necroticans is preventable by vaccination, such studies should be undertaken. This paper outlines the story of pigbel and its control in PNG.
Duffy phenotypes were determined for 314 Malaysian Orang Asli. The most common gene, Fya, was present in 313; there were no Duffy negative individuals. A previous study found evidence of Plasmodium vivax infection in 5 of 7 Orang Asli reported to be of the Duffy negative genotype. In this study, 5 of the 7 previously tested Orang Asli were retested in triplicate, and each of the 5 was found to be Duffy positive, having the Fya gene and a phenotype of Fy (a + b-).
Clinical studies were carried out on mild Indian sickle cell anaemia in Malaysia, and genetic and fertility studies were carried out on 101 families with and without sickle-cell haemoglobin (Hb S). The Indian sickle cell anaemia patients reached adulthood, and pregnancies and deliveries were uneventful without blood transfusion. There was no foetal wastage and the number of children produced was not significantly different from that in families without Hb S. 28 Indian patients hospitalized with Plasmodium falciparum malaria infection were also examined for their beta S genotype. P. falciparum malaria infection occurred much more frequently in individuals without Hb S than in Hb S carriers.
Malaysian, British and New Zealand soldiers were tested for evidence of infection with Rickettsia tsutsugamushi after several weeks' exposure to the infection during field exercises in Malaysia. 39 (5.0%) of 787 British and New Zealand soldiers developed immunofluorescent antibody (IFA) to R. tsutsugamushi to a titre of 1:50 and two (0.3%) to a titre of 1:100. 11 (1.5%) of 751 Malaysian soldiers also developed low titres less than or equal to 1:100. These low antibody levels were not correlated with clinical disease, and their significance is unknown. Seven (0.9%) of the Malaysians showed an IFA rise to greater than or equal to 1:200, and three of these experienced febrile illnesses, one lasting two weeks. An additional eight Malaysian soldiers had an IFA titre of greater than or equal to 1:400 when first tested and six of these also had a Proteus OXK agglutinin titre of greater than or equal to 1:160, indicating infection shortly before the study.
We used Bayes' theorem to calculate the probability of enteric fever in 260 patients presenting with undiagnosed fever, without recourse to blood or stool culture results. These individuals were divided into 110 patients with enteric fever (63 culture positive, 47 culture negative) and 150 patients with other causes of fever. Comparison of the frequencies of occurrence of 19 clinical and laboratory events, said to be helpful in the diagnosis of enteric fever, in the two groups revealed that only 8 events were significantly more frequent in enteric fever. These were: a positive Widal test at a screening dilution of 1:40; a peak temperature greater than = 39 degrees C; previous treatment for the fever; a white blood cell count less than 9 X 10(6)/litre; a polymorphonuclear leucocyte count less than 3.5 X 10(6)/litre; splenomegaly; fever duration greater than 7 d; and hepatomegaly. When the probability of enteric fever was determined prospectively in 110 patients, using only 6 of these discriminating events, the probability of patients with a positive prediction having enteric fever (diagnostic specificity) was 0.80 (95% confidence interval: 0.68 to 0.91) and the probability of those with a negative prediction not having enteric fever (diagnostic sensitivity) was 0.92 (0.85 to 0.99). Using all 19 events did not alter the diagnostic specificity or diagnostic sensitivity. This study shows that a small number of clinical and laboratory features can objectively discriminate enteric fever from other causes of fever in the majority of patients. Calculating the probability of enteric fever can aid in diagnosis, when culturing for salmonella is either unavailable or is negative.
Seven villages in Banggi Island, Sabah, Malaysia, were surveyed four times to evaluate the roles of local mosquitoes as vectors of malaria and Bancroftian filariasis. 11 species of Anopheles were found biting man. 53.9% of the anophelines caught were An. flavirostris, 27.1% An. balabacensis, 6% An. donaldi and 4.2% An. subpictus. Infective malaria sporozoites, probably of human origin, were found in two of 336 An. flavirostris and 12 of 308 An. balabacensis. Sporozoites, probably of a non-human Plasmodium, were found in An. umbrosus. Nine of 1001 An. flavirostris and four of 365 An. balabacensis harboured L2 or L3 filarial larvae identified as those of Wuchereria bancrofti. This is the first record of An. flavirostris as a natural vector of malaria and W. bancrofti in Sabah.
A survey of 308,101 schoolchildren conducted in 10 of 11 states in Peninsular Malaysia revealed that 10.7% have Pediculus humanus capitis infestation. The results of treatment with 1%, 2% and 5% DDT in coconut oil in 374 cases reveal cure rates of 3.5%, 15.8% and 51.3%, respectively, suggesting that the head louse has probably developed resistance to this insecticide in Malaysia.