Needs of exploring the burden of recent onset seizures due to neurocysticercosis and challenges in southeast Asia focusing on scenario in Malaysia.

Seizures due to neurocysticercosis (NCC) is a neglected human-to-human transmitted disorder and an emerging problem worldwide. A substantial portion of recent onset seizures is known to be attributed to NCC in Taenia solium (T. solium) endemic areas where populations which neither raise pigs nor eat pig meat are also at risk. High prevalence of NCC causing epilepsy has been reported in the underdeveloped areas of Southeast Asia (SEA) however, only fragmentary information on its incidence is available in countries like Malaysia. In Malaysia T. solium infection was previously thought to be infrequent due to Muslim population majority and the religious prohibition of consuming pork, but it is not totally absent. There is an evident lack of knowledge and awareness of the actual burden, routes of transmission, and the impact of NCC in this region. The problem is assumed to be more prevalent particularly in cities because of the frequent inflow of possibly T. solium infected individuals or carriers among those who migrate from neighboring endemic countries to Malaysia. The issue of imported cases that are likely to be emerging in Malaysia is highlighted here. An accurate quantification of regional burdens of epilepsy due to NCC in Malaysia is warranted considering the disease emergence in its neighboring countries. It is suggested that the importance of NCC be recognized through quantification of its burden, and also to collect epidemiological data for its subsequent elimination in line of World Health Organization's mission for control of cysticercosis as a neglected tropical disease. In this review the need as well as a strategy for neuro-care center screening of epilepsy cases, and various issues with possible explanations are discussed. It is also proposed that NCC be declared as a reportable disease which is one of the eradicable public health problems in SEA.

A recombinant antigen-based IgG4 ELISA for the specific and sensitive detection of Brugia malayi infection.

An IgG4 ELISA based on a novel recombinant antigen was evaluated for detection of Brugia malayi infection, using 2487 sera from various institutions: 2031 samples from Universiti Sains Malaysia, 276 blinded sera from 2 other institutions in Malaysia, 140 blinded sera from India and 40 blinded sera from Thailand. These sera were from various groups of individuals, i.e., microfilaraemics, chronic patients, endemic normals, non-endemic normals and individuals with other parasitic and bacterial infections. Based on a cut-off optical density reading of 0.300, the IgG4 ELISA demonstrated specificity rates of 95.6-100%, sensitivity rates of 96-100%, positive predictive values of 75-100% and negative predictive values of 98.9-100%. These evaluation studies demonstrated the high specificity and sensitivity of this test for the detection of active B. malayi infection. Thus, the IgG4 ELISA would be very useful as a tool in diagnosis and in elimination programmes for brugian filariasis.

Specificity and sensitivity of a rapid dipstick test (Brugia Rapid) in the detection of Brugia malayi infection.

A total of 753 serum samples from 6 institutions in 3 countries (Malaysia, Indonesia and India) were used to evaluate an immunochromatographic rapid dipstick test, Brugia Rapid, for diagnosis of Brugia malayi infection. The samples comprised sera from 207 microfilaria-positive individuals and 546 individuals from filaria non-endemic areas. The latter consisted of 70 individuals with soil-transmitted helminth infections, 68 with other helminth infections, 238 with protozoan infections, 12 with bacterial and viral infections and 158 healthy individuals. The dipstick is prepared with a goat anti-mouse antibody control line and a B. malayi recombinant-antigen test line. First, the dipstick is dipped into a well containing diluted patient serum, thus allowing specific anti-filarial antibody in the serum to react with the recombinant antigen. Then the dipstick is placed into an adjacent well containing reconstituted anti-human IgG4-gold. After 10 min, development of 2 red-purplish lines denotes a positive result and one line indicates a negative reaction. The overall results of the evaluation showed 97% sensitivity, 99% specificity, 97% positive predictive value and 99% negative predictive value. Brugia Rapid is thus a promising diagnostic tool for detection of B. malayi infection, and would be especially useful for the brugian filariasis elimination programme.

Antibodies to somatic L3 antigen not protective against Brugia malayi infection.

Western blot analysis of infective larvae (L3) antigen of Brugia malayi were performed on 200 sera from six groups of individuals: 36 samples from B. malayi microfilaremic individuals; 10 samples from individuals with elephantiasis; 50 and 20 samples from amicrofilaremic individuals in a B. malayi endemic area with no anti-filarial IgG4 antibodies (towards microfilaria and adult worm antigens) and samples with high titres of the anti-filarial IgG4 antibodies respectively; 50 samples from non-endemic normals and 34 samples from geohelminth-infected individuals. After protein transfer, PVDF membrane strips were successively incubated with blocking solution, human sera, monoclonal anti-human IgG4 antibody-HRP and developed with luminol chemiluminescence substrate. 28/36 (78%), 1/10 (10%) and 16/20(80%) of sera from individuals with microfilariae, elephantiasis and amicrofilaremic individuals with high titers of anti-filarial IgG4 antibodies respectively recognized L3 antigenic epitopes; the dominant and consistent antigenic bands were of approximately MW 43 kDa, 14 kDa, 15 kDa and 59 kDa. The rest of the sera were unreactive. This study showed that microfilaremics may or may not mount a notable antibody response to somatic L3 antigens, thus lending evidence that antibody response to this antigen is not protective against establishment of Brugia malayi infection.

Experimental chemotherapy of lymphatic filariasis. A review.

An intense global collaborative effort under the leadership of the Steering Committee of the Filariasis Scientific Working Group of the Tropical Diseases Research Programme, World Health Organization, has brought together researchers, pharmaceutical chemists and clinicians in the development and search for antifilarial compounds which are more effective and more convenient to administer than diethylcarbamazine citrate, the current drug of choice for lymphatic filariasis. The Brugia spp.-rodent model has been used extensively for the primary screening and B. pahangi infections in the dog or cat for the secondary screening, of potential filaricides. Recently, the leaf-monkey (Presbytis spp.) infected with subperiodic B. malayi or Wuchereria kalimantani has been used for the tertiary evaluation and pharmacokinetic studies of compounds which have shown effectiveness in the primary and secondary screens. Both P. cristata and P. melalophos are extremely susceptible to subperiodic B. malayi infection, but the former is a better host as a higher peak microfilaremia and adult worm recovery rate were obtained. Although more than 30 potential filaricides have been evaluated in the tertiary screen, only a few compounds have shown some promise against lymphatic filariasis. CGP 20376, a 5-methoxyl-6-dithiocarbamic-S-(2-carboxy-ethyl) ester derivative of benzothiazole, had complete adulticidal and microfilaricidal activities against the parasite at a single oral dose of 20 mg kg-1. However, as the compound or its metabolites caused hepatotoxicity, its clinical use in the present formulation is not recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

[Description of Onchocerca dewittei n. sp. (Filarioidea), parasite of Sus scrofa, in Malaysia (author's transl)]. / Description d'Onchocerca dewittei n. sp. (Filarioidea) chez Sus scrofa en Malaisie.

Onchocerca dewittei n. sp. was collected from a wild Boar at the metatarse level (tendons and subcutaneous connective tissue); it can be differentiated from other species by the female cuticle showing straight ridges which overlap in the lateral fields, and by its relatively thick microfilaria (length 228-247 mu and width 6-7 mu). This suidean Onchocerca displays some primitive characters such as straight ridges and persistency of ten pairs of caudal papillae in the male; but as a whole this species is undoubtedly more highly evolved than O. raillieti Bain, Müller and coll., 1976, a parasite of Equidae.

Studies on immunization against Brugia malayi infection in the rhesus monkey.

Recent studies on immunity to helminthic infection have shown that some degree of protective immunity may be stimulated by inoculations of attenuated living worms or their metabolites. The present experiments were designed to observe the effects of attempted immunization in the rhesus monkey by the use of attenuated infective larvae of Brugia malayi.Some effect was observed in animals inoculated with larval incubate, in which microfilaraemia did develop, but at low levels and for short durations. However, the most strking finding was that persistent immunity to challenge infections (expressed as failure to cause microfilaraemia) was obtained in animals vaccinated with large numbers (200) of infective larvae attenuated by X-irradiation at 20 000 R.Experiments with different numbers of larvae attenuated by different doses of irradiation suggest that there is an optimum combined effect of these two factors in eliciting functional antibody in a quantity sufficient to prevent patent infection in Malayan filariasis.