A strain of Clostridium bifermentans individualized as serovar malaysia (C.b.m.) according to its specific H antigen is toxic to mosquito and blackfly larvae when given orally. The toxicity occurs in sporulated cells which contain, in addition to spores, proteinic parasporal inclusion bodies and feather-like appendages; the amino acid content of the inclusion bodies is similar to that of Bacillus thuringiensis serovar israelensis (B.t.i.) and B. sphaericus crystals. The toxicity to Anopheles stephensi is as high as that of B.t.i. and the best strains of B. sphaericus. Culex pipiens is somewhat less susceptible, and Aedes aegypti much less. Pure parasporal inclusion bodies, isolated by ultracentrifugation on sucrose gradients, are highly toxic to mosquito larvae. The larvicidal power is destroyed by heating at 80 degrees C or by treatment with 50 mM NaOH. It is preserved by freeze-drying. The innocuity to mice of the sporulated cells is shown by different routes of administration: force-feeding, percutaneous, subcutaneous, intraperitoneal or intravenous injections. The potential for the biological control of mosquito and blackfly larvae is suggested.
Five local Malaysian patients with clinical manifestations consistent with lymphatic filariasis were referred to our medical centre between 2003 and 2006. Although no microfilariae (mf) were detected in their nocturnal blood samples, all were diagnosed to have lymphatic filariasis on the basis of clinical findings and positive serology results. PCR on their blood samples revealed that two of the patients were infected with Brugia pahangi, an animal filarial worm hitherto not known to cause human disease in the natural environment. All the patients were successfully treated with anti-filarial drugs: four patients were treated with a combination of diethylcarbamazine (DEC) and albendazole, and one with doxycycline. Four of them were residents of Petaling Jaya, a residential suburbia located 10 km southwest of Kuala Lumpur city, Malaysia. The fifth patient was a frequent visitor of the suburbia. This suburbia has no history or record of B. malayi infection. The most likely vector of the worm was Armigeres subalbatus as extensive entomological surveys within the suburbia revealed only adult females of this mosquito species were infected with B. pahangi larvae. Wild monkeys caught in the suburbia were free from B. pahangi mf, but domestic cats were mf positive. This suggests that infected cats might be the source of the zoonotic infection in the suburbia.
Because of the risk of introduction of yellow fever to South-East Asia, comparative studies were made of yellow fever vaccination in Malayans who had a high prevalence of antibody to related viruses and in volunteers without related antibody. The proportions of positive neutralizing antibody responses to subcutaneous vaccination with 17D vaccine were not significantly different between volunteers with and without heterologous antibody but the degree of antibody response was greater in those without. The ID(50) of 17D in both groups was about 5 mouse intracerebral LD(50). Multiple puncture vaccination with 17D gave a much lower response rate than subcutaneous vaccination in volunteers with heterologous antibody. In both groups subcutaneous doses of about 50 mouse intracerebral LD(50) gave larger antibody responses than higher doses. The neutralizing indices and analysis of results were calculated by a method based on the survival time of the mice. This method, which has advantages over that of Reed & Muench, is fully described in an annex to this paper.
A case of human eye infection caused by Brugia pahangi was reported in 2010 in a semi rural village in Selangor, peninsular Malaysia. Our report here reveals results of investigation on the vector and animal host for the transmission of the infection. We conducted entomological survey and cat blood examination in the vicinity of the patient's home. The mosquito species Armigeres subalbatus was incriminated as the vector, whereas cat served as the reservoir host.
Surface engineering of super paramagnetic iron oxide nanoparticles (SPIONs) favor the tagging of any molecule or compound onto it, encapsulating them with a biopolymer make them biocompatible and favor slow release of loaded molecules. Recovery of SPIONs is easier as they obey to external magnetic field. In this study, SPIONS were used for mosquito larvicidal activity after surface engineered with oleic acid to favor the tagging of Cyfluthrin (mosquito larvicidal agent), it was then encapsulated with gum polysaccharide derived from Azadirachta indica and Araucaria heterophylla. Every stage of coreshell formation was microscopically and spectroscopically characterized. The coreshell SPIONs produced using Azadirachta indica and Araucaria heterophylla gum derived polysaccharide encapsulation were found to be the size around 80 nm. Thus, prepared coreshell SPIONs was subjected for mosquito larvicidal activity against Culex sp. The coreshell SPIONs was efficiently killing the mosquito larva and its impact was studied by percentage mortality studies.
The genus Mansonia is divided into two subgenera, Mansonia and Mansonioides. The subgenus Mansonioides includes the important vectors of lymphatic filariasis caused by Brugia malayi in South and Southeast Asia. Six species of this subgenus are vectors of two types of brugian filariasis, periodic and subperiodic. All six species, viz Mansonia bonneae, Ma. dives, Ma. uniformis, Ma. annulifera, Ma. annulata and Ma. indiana are present in this country. The ecological factors governing the larval and adult biology and their control measures are discussed.
(1) The effect has been studied of the oral administration of supplementary thiamine on the thiamine content of milk from sixteen women, whose initial thiamine content was low ; and of the parenteral administration of thiamine to ten women, some of whom initially showed mild, clinical symptoms of beriberi.
(2) The response in the milk content of thiamine to supplementary thiamine, administered either orally or by injection, showed marked variation in different women. While comparatively small doses taken by mouth evoked a marked response in some women, fairly large doses administered by injection failed to produce much response in others.
(3) In some women, a marked increase in the thiamine content of their milk occurred soon after the administration of thiamine, either orally or parenterally. In others, the response was slow and meagre.
(4) The highest thiamine level obtained in a sample of milk was 38.9 ug./100 ml., after the injection, twice daily, of 20 mg. thiamine for six days — a total intake of 240 mg. of thiamine parenterally. The initial milk thiamine level in this case was 2.3 ug./100 ml., but had increased to 16.2ug./100 ml., by the supply of a good diet alone, before the course of injections was commenced.
(5) It would appear, that, in cases where the thiamine content of the milk is low, initial parenteral administration of thiamine must be supplemented by a continued intake of additional thiamine, if a satisfactory level of thiamine in the milk is to be maintained.
The levels of susceptibility of C. p. fatigans larvae from four different localities in Malaya to DDT, dieldrin, malathion, fenthion, diazinon and Sevin have been studied; their toxicity was: diazinon > fenthion > malathion > dieldrin > DDT > Sevin.Larvae from different localities showed a wide range of susceptibility to the chlorinated hydrocarbon insecticides, dieldrin (40x) and DDT (10x), but the organophosphorus compounds and the carbamate compound, Sevin, gave consistent results from all localities. One strain from a rural area (Lamir) was the most susceptible to all insecticides and has been used as a reference strain for related studies on the development of resistance.