An attempt to study the economic loss arising from Schistosoma japonicum infection and the benefits derived from treatment.

From the northern and southern portions of Leyte Province, which are endemic for schistosomiasis, a total of 801 infected individuals were interviewed, examined, and classified into mild, moderate, severe and very severe forms of disease with an assumed loss of working capacity for each category. The frequency rate or number of spells of illness for the past year under observation were correlated with the degree of incapacity to get the total days lost per person per year. Following a series of computations, of which the disability rate was considered as the most important, a total of 45.4 days lost per infected person per year was arrived at. Treatment of the disease with praziquantel was carried out and the patients were followed up one year after treatment, at which time the same methodology was applied. The results show that the 45.4 days lost prior to treatment went down to 4 days lost. There was an economic gain of 41.4 days as a result of treatment. This can be expressed in terms of financial value if we consider half of the infected cases as breadwinners receiving a minimum wage. It should be noted that a number of assumptions in this study were made. It is, however, hoped that this work will serve as a guide and a starting point for others to carry out related studies on economic loss and subsequent economic benefits to justify budgetary requests/allocations for the implementation of various preventive and control measures.

Application of alcohol- or acetone-fixed Schistosoma eggs as an alternative to lyophilized eggs for the circumoval precipitin test.

Antigenicity of Schistosoma mansoni and S. japonicum eggs preserved in ethanol or acetone were assessed in a circumoval precipitin (COP) assay. The egg antigens were found to retain sufficiently their COP reactivity for the diagnosis of both schistosomiasis mansoni and japonica, although their reactivity became lower than that of lyophilized eggs. These alternative preparations for COP tests have advantages, such as keeping eggs directly in fixatives soon after the egg-purification process. Furthermore, evaporation-process may cause eggshell cleavages which facilitate the reaction. The possible usefulness of those eggs in COP assays in local endemic areas is discussed.

An attempt to study the case fatality rate in Schistosoma japonicum infection in the Philippines.

As a sequence to a cross-sectional study on the clinical gradient of the disease by Pesigan et al., (1965) a follow-up of the subjects in that study was made after 12 years. Of the 135 untreated cases followed up, 23 (17.04%) died from various causes of which 12 (8.89%) had signs and symptoms attributable to schistosomiasis as the immediate cause or one of the main causes of death. This occurred in 1 to 11 years with an average of 5 years, which corresponds roughly to 1.78% of the infected cases per year. This is considered a conservative estimate because in the other deaths due to other diseases, schistosomiasis is a contributory cause. A diminishing severity of the disease was observed among the surviving patients which could imply that they must have developed some degree of immunity to the disease.

Experimental infection of Oncomelania quadrasi with Paragonimus ohirai.

Two hundred Oncomelania quadrasi collected from Leyte, Philippines were exposed to infection with Paragonimus ohirai, a rodent type lung fluke. In a group, each snail was exposed individually to 10 miracidia hatched from eggs which were brought from Japan to the Philippines. In another group, 100 snails were placed in a Petri dish and P. ohirai miracidia were added to provide 10 per snail. The observations were made each successive week after exposure. All the snails examined were positive for the larvae of P. ohirai. Nine-ten weeks after exposure, many cercariae were recognized. It was proved that O. quadrasi is highly susceptible to P. ohirai.

Schistosomiasis japonica in Barrio San Antonia, Basey Samar, in the Philippines: III. The plasma circumoval precipitin test-procedure and use in epidemiologic studies.

A plasma circumoval precipitin test is proposed as the basic diagnostic tool for epidemiologic studies on schistosomiasis japonica in the Philippines. The collection of plasma, the preparation of the COP test slide, and the reading and interpretation of results are described in detail with pertinent comments. The cost, advantages and usefulness of the test are also discussed.

Schistosomiasis japonica in Barrio San Antonio, Basey, Samar in the Philippines: II. Quantitative fecal examination and circumoval precipitin tests.

An improved quantitative stool examination technique (MFCT) and two variations in the performance of the circumoval precipitin test, one using whole serum (SCOPT) and the other employing the eluate from finger prick blood dried on filter paper (FPCOPT), were evaluated in a field study to detect infection with S. japonicum among residents of an endemic barrio in Samar. The sensitivity of SCOPT was above 90%, that of MFCT was between 80 to 90%, while that of FPCOPT was only about 50%. Intensity of infection as judged by fecal egg excretion and duration of infection as indicated by age were shown to be determinants of serum reactivity (and hence sensitivity of the two serodiagnostic tests). The relative insensitivity of FPCOPT observed in this work, also evident in some published data of previous workers, puts to doubt the wisdom of using this technique as the procedure of choice in epidemiologic surveys in the Philippines as currently favored in that country. Atypical positive reactions in circumoval precipitin tests using whole serum were detected which may make the differentiation of relatively recent from old infections possible.

Ambilhar in the treatment of Schistosoma japonicum infection and as an egg suppressant for mass treatment.

Ambilhar or niridazole at a dose of 25 mg per kg body weight for 7 days was found ineffective against Sl japonicum infection. Longer period of treatment for 10 to 14 days gave impressive stool negative conversion and egg reduction rates but with moderately severe reactions, the most alarming of which was hallucination. To minimize toxicity, the daily dose was reduced but given for a longer duration so that the total amount of the drug given per kilogram body weight was approximately the same as the 25 mg pre kg per day for 10 to 14 days. Of the two treatment schedules tried, the 15 mg per kg per day for 24 days was found relatively effective. Although the drug with this treatment regimen was well tolerated, a drop-out of 50.8% was observed. Ambilhar was therefore tried as an egg suppressant. With a 10-day treatment, all patients were again positive after 6 months. Egg reduction rates during the 6 months stool follow-up ranged from 69.8 to 93.5%. Further trials using this dose to be repeated every 3 to 6 months is contemplated.

Agro-engineering and sanitation improvement in the control of schistosomiasis japonica in the Philippines: a review.

Measures that would change the habitat of the snails were found to prevent its breeding. Among these are clearing and drainage of waterlogged areas; filling of depressions where filling materials are available; ponding of areas which cannot be drained, and improved rice culture. The degree of success in snail control depends to a large extent on the amount of change brought about in the habitat. The more radical the change, the greater the reduction in snail density. It can be expected that improvement in sanitation in the form of toilet construction and use, provision of safe water supply, building of footbridges and the control of stray animals will bring a further decline in the transmission of the disease. Studies have shown that perfect sanitation in the form of toilet construction and use will reduce transmission by about 75%, the other 25% being contributed by lower mammals. Agro-engineering control measures are presently being carried out intensively in 7 town of Leyte, with food assistance from the UN/FAO World Food Program being given to volunteer workers as incentives for them to work. Snail evaluation after 2 years has shown a snail reduction by 72% in the areas covered. It may be mentioned here that sanitation improvement, especially latrine construction, is an ongoing program of the Department of Health in all rural areas.