Seven of the 18 species of lowland forest terrestrial and semi-arboreal murids were found naturally infected with Breinlia booliati. Of these, two species, Rattus sabanus and R. cremoriventer, were found to be the most preferred hosts. None of the murids from the highland, field or human-inhabited areas was infected. This could have been due more to the greater scarcity of the vectors in these habitats than to the susceptibility of the hosts. The absence of this parasite in the squirrels examined may be attributed either to host specificity or to the normal activity cycles or vertical stratification of the vectors, separating them in space and/or time from the squirrels. The pattern of dispersion of the parasite is influenced by the wide distribution of suitable hosts, and the hypothesis that the parasite is of forest origin is discussed.
Breinlia booliati exhibited nocturnal subperiodicity in its natural host, Rattus sabanus in contrast to experimentally infected laboratory-reared albine rats which showed irregular fluctuations of microfilariae throughout the 24 hour cycle. All the infected albino rats showed a prepatent period between 11-14 weeks postinoculation. Three patterns of microfilaraemia were discerned during the course of infection 38/49 rats displayed a single peak, 4/49 displayed 2 peaks about 12-15 weeks apart and 7/49 showed a sustained high plateau-like pattern of microfilaraemia. Cortisone had no effect on microfilarial levels when administered to rats near postpatency and some at postpatency.
The development of Breinlia booliati is described in its natural host, Rattus sabanus and in an inbred strain of laboratory albino rat. The growth of the parasite is similar in both the rat hosts. The third moult occurs between six-eight days and the final moult between 24-28 days. Larvae were recovered initially from the skin and carcass. After five weeks, developing stages were seen only in the thoracic and abdominal cavities, the site of development of the adult worms. Worms became sexually mature by 11-12 weeks and there was considerable growth in length of the female worms after this stage.
A survey of workers and families resident in an oil palm estate in Malaysia revealed high incidence of parasitic infections. The commonest parasites are T. trichiura (56%), A. lumbricoides (52%), hookworm (28%), Entamoeba coli (11.3%) and Giardia lamblia (11.3%). Mixed infections by two or more parasites was seen in 46% of the subjects. Anaemia was present in 70% of children with hookworm infection. Eosinophilia was observed in 69% of subjects. One each of Hymenolepis nana and Hymenolepis diminuta infection was detected. This is the first report of Hymenolepis diminuta infection in man in Malaysia.
The prevalence of Capillaria hepatica (Bancroft, 1893) infection in a total of 2324 rats trapped from 25 localities in West Malaysia was 15.5%. Infection rates in males (16.0%) and females (15.1%) are similar. A significantly higher percentage of adults (18.1%) than young (7.7%) was infected. Capillaria hepatica infection rates among urban (0.7%) and jungle (0.0%) rats was very low as compared to field rats (17.7%) trapped from agricultural areas such as oil palm estates and rice growing areas. Prevalence of C. hepatica infection in rats is not evenly distributed throughout West Malaysia. There seem to be localised foci of infection. In some areas as many as 77.8% of the adult rats are found to be infected while in other areas the same species of rats are found free of infection.
The indirect immunofluorescence test using sonicated microfilariae of Brugia malayi has been evaluated on 173 sera from patients and persons exposed to Wuchereria bancrofti and B. malayi in endemic areas of Peninsular Malaysia. In the microfilaria-negative group, without signs and symptoms of filariasis 55/62 sera (89%) had titers of 1:16 and less. In the microfilaremic groups and in the amicrofilaremic cases with clinical filariasis, all the sera tested were positive, with the antibody titers ranging generally from 1:16 - 1:256. Cross-reaction tests were done on 16 samples of onchocerciasis sera from West Africa using sonicated antigen as well as antigen-coated CNB1-activated sepharose. Antibody titers were detected in all the sera. The usefulness of the sonicated microfilarial antigen in serodiagnosis of filariasis is discussed.
Levels of immunoglobulins G, A, M and E as well as complement components C3c and C4 have been determined in populations in various endemic areas in Peninsular Malaysia and also in filariasis patients. High immunoglobulin levels were seen. In the microfilarial-negative group IgG was 2009 mg% while IgE was 3967 I.U./ml. In the filariasis group, Wuchereria bancrofti patients had significantly higher levels of IgG, IgM and IgE, namely, 3314 mg%, 804 mg% and 18400 I.U./ml respectively. The significance of these levels is discussed.
The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samples obtained from patients and persons exposed to Wuchereria bancrofti and Brugia malayi in endemic areas of Peninsular Malaysia. A crude extract of adult worms of the rat filaria, Breinlia booliati, was used as the antigen. When a titer of 1:16 was taken as negative, positive IHA test rates in sera from microfilaria-negative persons in endemic areas, microfilaremic cases, and patients with clinical filariasis were 13%, 75%, and 80%, respectively. Results of the IHA test correlated well with results obtained with the indirect fluorescent technique.
The indirect fluorescence antibody technique has been employed to study the prevalence of toxoplasma antibodies in Singapore. 42.5% of clinically suspected cases of toxoplasmosis showed antibody titres. Of these, 17.5% had titres greater than or equal to 1.64. Malays and Indians have higher positive rates compared to the main ethnic group, the Chinese. Antibody titres are found in both males and females and span through the various age groups. The possible mode of transmission is discussed and the importance of congenital toxoplasmosis is indicated.
A case of rare retinal lesion occurring in a young girl suffering from lepromatous leprosy is described. Fundus lesions in leprosy are extremely rare but do occur in some cases without causing any threat to vision. Their response to antileprotic treatment is not clearly known.
A rare case of pilocarpine-induced retinal detachment occurring in the only useful myopic eye of a young Chinese woman is described. Problems of treating raised intraocular pressure in high-risk cases of retinal detachment are discussed.
Raised intraocular pressure (lOP) is generally held responsible for causing visual loss in chronic simple glaucoma. It is therefore desirable that a safe level of lOP be maintained all the time. Elevation of lOP with change of body position has been suggested as one of the factors which result in tissue damage in low tension as well as in primary wide open angle glaucoma. Postural behaviour of lOP was therefore studied in 58 normal and 30 glaucomatous Malaysian eyes. Clinical significance and possible pathogenesis of abnormal postural response of lOP has been discussed. More application of this simple procedure is advocated.
A retrospective study of 37 intraocular foreign bodies treated over a five-year period is presented. Their aetiology, complications and visual results are discussed in the light of recent development in the management of serious ocular trauma.
Study site: Hospital Kuala Lumpur, Malaysia (UKM unit)