The "crowding effect" phenomenon in Ascaris lumbricoides.

Ascaris lumbricoides worm populations were studied from 150 Filipino children (0-14 years) dewormed with pyrantel pamoate (Combantrin) or oxantel-pyrantel pamoate (Quantrel). Populations were classified according to intensity of infection: very light, light, moderate or heavy. A total of 2072 adult worms were sexed (939 males and 1133 females) and weighed. Descriptive statistics on the weights obtained from each sex were derived and one-way ANOVA was performed to compare the mean weights among the 4 intensity classes. Linear regression analysis (individual worm weight versus total worm burden) was also employed to equalize the possible influence of host factors. Statistical analysis revealed that mean weights of both sexes were significantly different and decreased as worm burden increased. This strongly suggests that the "crowding effect" phenomenon may also apply to Ascaris lumbricoides, and not only to tapeworms, as reported in the literature.

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.

Reinfection and infection rates of ascariasis in relation to seasonal variation in the Philippines.

Stool examinations of 320 primary school children for eggs of Ascaris revealed a prevalence of 74.0 percent. Reinfection and infection rates were determined on a monthly basis with egg-positive subjects treated correspondingly. Due to dropouts of subjects, only 154 children completed the 12-month observation. About 15% of children remained negative after treatment during one year but 85% got reinfected, with those reinfected only once being the highest then those reinfected twice, followed by those reinfected more than twice in a year. Of the 203 Ascaris worms collected 69% were females and 31% were males with a sex ratio of 2.4 females to one male; 73% were mature and 27% were immature females; 70% were mature and 30% were immature males; mean number of worms per child was 2.6. The mean length and weight of female was 22.9 cm and 3.6 gms respectively while for males it was 16.1 cm and 1.7 gm respectively. The graph showing amount of rainfall, reinfection and infection rates of ascariasis revealed the presence of two major peaks both in the reinfection and infection rates noted in December-January and May-June. Likewise, the rainfall also peaked twice namely in August and October. It appears that ascariasis reinfection or transmission is highest when rainfall is minimal and lowest when rainfall is at its highest peak. Based on the peaks of reinfection and infection, it is suggested the school children be dewormed in June and in December each year for at least three years.

Treatment of falciparum malaria with clindamycin.

Foram estudados dois grupos de pacientes portadores de malaria por P. falciparum que receberam o antibiotico durante sete dias. A um desses grupos, com 24 pacientes foi administrada a dose de 300 mg/dia, dividida a cada 12 horas. A via endovenosa foi utilizada durante tres dias e, a seguir, a via oral por mais quatro dias. Ao outro grupo, de 12 pacientes, administrou-se 600 mg/dia de clindamicina seguindo identico regimen do grupo anterior.Em testes de resistencia a cloroquina, evidenciou-se positividade em cinco pacientes do primeiro grupo e tres do segundo, a nivel de R-II. Ambos os regimes provaram efetividade na cure de malaria por P. falciparum

Clinical trials of broad spectrum anthelmintics against soil-transmitted helminthiasis.

Clinical trials on the three broad spectrum anthelmintics against trichuriasis, ascariasis and hookworm infection were carried out in a rural community in Irosin, Sorsogon. Flubendazole (Fluvermal) appears to be a promising drug against trichuriasis particularly when periodic mass treatment of a community is carried out. Mebendazole (Antiox) also appears to be promising given as single dose during mass treatment of soil-transmitted helminthiasis. As shown in previous studies, oxantel-pyrantel (Quantrel) should be given at 15 mg/kg body weight at 12-hour intervals or 20 mg/kg body weight single dose rather than 10 mg/kg body weight in a single dose when treating trichuriasis.

Distribution and density of mosquitoes in two endemic areas for bancroftian filariasis in Sorsogon, Philippines.

Mosquito density in Rangas where abaca is in abundance is much higher, almost twice, than that of Putiao where abaca is absent. The adult density of Aedes poecilus over Aedes ananae in the two areas combined is 3 to 4 times whereas the larval density of the former is much lower than Aedes ananae. The banana axils is a favorite breeding place for Aedes poecilus but may also utilize the abaca axils. This finding is very favorable in the transmission of bancroftian filariasis because this species of banana is planted around houses even closer to human dwelling than the abaca plants. Aedes poecilus being more anthropophylic than zoophylic can be domesticated as Culex quinquefasciatus and Aedes aegypti which again is a factor in favor of ideal transmission of the disease. The fact that bananas are planted around houses both in villages and towns, transmission of the disease could easily occur in both places, which should be borne in mind when planning a control program. The number of dissected mosquitoes is too small to be of significance in vector determination.

Current status of schistosomiasis japonica in Sorsogon Province, Republic of the Philippines.

A resurvey of Irosin and the eight municipalities surrounding it for schistosomiasis japonica using COPT and FECT was done in order to determine the status of the disease thirty years after it was first reported in the town of Irosin in 1947. In Irosin, the results by FECT showed that there was a decrease in prevalence from 5.7% to 2.8%, however, if by COPT, then there was an increase from 5.7% to 12.2%. There is a definite trend of the disease to spread from Irosin into the surrounding municipalities. Whereas in 1951, only Irosin and Juban have been established as endemic foci for schistosomiasis, the result of previous surveys by the schisto-unit at Irosin and the present study seem to indicate that the disease has spread into seven additional towns surrounding Irosin. In like manner, the snail intermediate host, Oncomelania quadrasi has a tendency to spread to outlying areas outside of Irosin and Juban.

Resistant levels of houseflies to six kinds of synthetic insecticides in the Philippines.

The resistant levels of houseflies to six kinds of insecticides: DDT, Pyrethrins, malathion, Sumithion, Baytex and DDVP, were examined on 15 strains collected in the Philippines. It was found that most housefly colonies in the Philippines showed higher susceptibility to those insecticides than the Takatsuki strains, especially to DDT. The range of LD50 values to malathion were between 1.775 microgram and 0.0975 microgram per fly. Among 15 strains collected in the Philippines, 7 showed higher LD50 values to malathion than the Takatsuki strain. These values mean that the houseflies in the Philippines are increasing their resistance to malathion.

A comparative study of Trichomonas vaginalis prevalence in Filipino women.

A comparative study of Trichomonas vaginalis prevalence among Filipino women is presented herein. A total of 288 women randomly drawn from various sources, including Social Hygiene clinics, Health Centers, and Family Planning Centers in the Metropolitan Manila Area were examined for T. vaginalis. Nineteen or (6.8%) were found positive either by wet mount or stained smear methods. Prevalence was significantly higher among the group of single than married women and five times higher among the waitress/hostess group than in the housewife/other group. Infection was related to parity and is significantly higher among nulliparous women. Likewise, a significant relationship was observed between prevalence of infection and gravidity. Prevalence decreases with increasing gravidity. No relationship in prevalence was observed between the use and non-use of contraceptives, and the method of contraceptive used. There was no significant association between the presence of the parasite and symptoms.

Observation on biting midge infestations on Mamburao Beach, Mimdoro, Philippines.

The occurrence of biting midge infestation involving the species Leptoconops (Styloconops) spinosifrons Carter 1921 (Diptera, Ceratopogonidae) is reported from a beach resort in Mindoro Island, Philippines. The flies are most active between 0700 and 0900 hours, and again, between 1600 and 1800 hours; they are most abundant in the shoreline and sand beach area.

Schistosomiasis japonica in field rats in Leyte, Philippines.

Approximately 73% of wild caught field rats were found infected with schistosomiasis japonica as revealed by the finding of eggs in liver sections; 49% of rats showed eggs in histological sections of the large intestine and about 13% showed eggs in their stools. Male rats appear to have higher schistosomiasis infection rate then female rats and that rats caught from endemic areas with smooth or normal looking livers do not necessarily mean that they are not infected with schistosomiasis. Examination for miracidia using only 2-3 pellets of field rat's stool by Faust-Meleney egg hatching technique revealed that 58% of them were positive with a mean of 5 miracidia per rat. A slightly lower hatchability rate was observed among laboratory infected white rats. Our figures on hatchability of Schistosoma ova are higher than those obtained by Pesigan and his co-workers probably because we used freshly collected rat faeces.