An assessment of barangay health midwives' knowledge regarding tuberculosis case finding and treatment procedures in urban health centers of metropolitan Manila, Philippines.

A survey was done from August to September, 1992 to determine the level of knowledge of 48 barangay health midwives (BHW) from urban health centers in Metropolitan Manila with regards to tuberculosis case finding and treatment procedures, as recommended by the National Tuberculosis Control Program (NTCP) of the Department of Health. Questionnaires were administered by personal interview. A cut-off mark of 17 correct answers out of 23 or 74% was arbritrarily chosen to signify a satisfactory level of knowledge. Results revealed that a substantial proportion of midwives still have inadequate knowledge regarding casefinding, case holding and NTCP policies. Type of training (p < 0.01) and age (p < 0.05) were found to be significant factors affecting level of knowledge while length of service was found to be marginally insignificant (p = 0.06). It is therefore highly recommended that urban health midwives be subjected to more regular formal training to increase their level of competence in attaining the goals of the NTCP.

Larvicidal potential of five Philippine plants against Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say).

Five species of Philippine plants, reported in the literature to have insecticidal properties, were selected for investigation, namely: Anona squamosa ("atis" or sugar apple), Eucalyptus globulus ("bagras" or olive gum eucalyptus), Lansium domesticum ("lansones"), Azadirachta indica ("neem") and Codiaeum variegatum ("San Francisco" or croton). These were screened and assayed for their larvicidal potential against Aedes aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say) by exposing 3rd-4th instar larvae to seven different concentrations (two-fold dilutions starting from 100 g% up to 1.5625 g%) of the crude aqueous extract derived from fresh leaves. Three trials were performed for each species of mosquito and for each of the five plants to determine the average mortality rate at various concentrations after 24 and 48 hours exposure. Probit analysis using the NCSS program was employed to determine the LD50 and LD90 values in order to compare the larvicidal potency of the five plants and to compare the susceptibility of Ae. aegypti and Cx. quinquefasciatus. The extracts exerted maximum insecticidal activity after 48 hours exposure. Lansones and atis were the most effective against larvae of Ae. aegypti and Cx. quinquefasciatus, respectively. Ae. aegypti was more susceptible than Cx. quinquefasciatus with respect to lansones and neem but Cx. quinquefasciatus was more susceptible than Ae. aegyti with respect to eucalyptus, San Francisco and atis. These varying results are probably due to differences in levels of toxicity among the active insecticidal ingredients of each plant and in the physiological characteristics of the two mosquito species.

Comparative horizontal starch gel isoenzyme electrophoresis of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

Foot muscle tissue extracts from six lymnaeid species of the Indo-Pacific region [Lymnaea (Bullastra) cumingiana and L. (Radix) quadrasi from the Philippines, L. (R.) rubiginosa from Indonesia and Thailand, and L. (R.) viridis from Guam and Hong Kong] were subjected to horizontal starch gel isoenzyme electrophoresis and assayed for seven isoenzymes (AcP, AlP, CA, EST, LAP, CAT and GOT) to elucidate their taxonomic relationships. L. cumingiana exhibited banding patterns for EST, LAP and CAT uniquely different from the rest, thus supporting the hypothesis that it is a distinct species. Zymogram patterns for AlP, CA, EST and LAP attest to the close affinity between L. quadrasi and L. rubiginosa (Indonesia and Thailand). Minor differences suggest a closer relationship between the two geographical strains of L. rubiginosa than with L. quadrasi, lending support to the hypothesis that L. quadrasi is inseparable as a race or variety from the typical L. swinhoei Adams, which in turn is but a race of L. auricularia, which also encompasses L. rubiginosa. The two geographical strains of L. viridis from Guam and Hong Kong showed the greatest consistency with regards to similarity and congruence in banding patterns. Non-specific esterases (EST) were the most useful in distinguishing the six species from each other.

Comparative radular morphology of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

The radular morphology of Lymnaea (Bullastra) cumingiana was compared to that of five other Indo-Pacific lymnaeid "species", namely: L. (Radix) quadrasi (Philippines), L. (R.) rubiginosa (Indonesia and Thailand) and L. (R.) viridix (Guam and Hong Kong) in order to investigate the taxonomic relationship among the six species. Although all six species uniformly exhibited a unicuspid, slightly asymmetrical central (rachidian) tooth and tricuspid laterals, interesting differences were noted among the outer marginals. These were observed to be uniquely bicuspid in L. cumingiana, predominantly tricuspid in L. quadrasi, tetracuspid in L. rubiginosa (Indonesia and Thailand) and multicuspid in L. viridis (Guam and Hong Kong). Thus, the results support the hypotheses that L. cumingiana is a unique species compared to the rest, that L. quadrasi is closely related to L. rubiginosa (Indonesia and Thailand) and that the two geographical isolates of L. viridis have not diverged. Radular morphology was therefore found to have a limited significance in elucidating the taxonomic relationship between the six groups of lymnaeids studied.

Ecological observations on Lymnaea (Bullastra) cumingiana.

Field surveys conducted at Echague, Isabela and San Pablo, Laguna revealed that Lymnaea (Bullastra) cumingiana, the natural second snail intermediate host of Echinostoma malayanum in the Philippines, exhibits a moderate degree of diversity in its choice of habitats. Rice fields of all stages of development, stagnant shallow streams and springs are the main areas where the snail can be collected from at Echague, Isabela. However, they were absent in rice fields that had been extensively sprayed with molluscicides to control the "golden apple snail" (Ampullarius canaliculatus). In contrast, they were also very abundant in the highly eutrophic waters of Sampaloc lake, San Pablo, Laguna. L. cumingiana co-exists with various species of insects, snails, fish and plants in these habitats. Information on ecological characteristics affecting its distribution will be useful for those who wish to collect and study this species in the future.

Comparative shell morphology of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

Comparative shell morphology using both quantitative and qualitative parameters was employed to investigate the taxonomic relationship between the endemic Philippine species, Lymnaea (Bullastra) cumingiana and five other lymnaeid "species" in the Indo-Pacific region, namely: L. (Radix) quadrasi (Philippines). L. (Radix) rubiginosa (Indonesia), L. (Radix) rubiginosa (Thailand), L. (Radix) viridis (Guam) and L. (Radix) viridis (Hong Kong). Fifty randomly chosen adult specimens of each species were studied and compared, although only field-collected specimens were studied for the first four groups and laboratory-raised specimens for the last two group. Results strongly suggested that L. cumingiana is a distinct species among the rest. L. quadrasi, L. rubiginosa (Indonesia) and L. rubiginosa (Thailand) exhibited great affinity towards each other. Likewise, the two geographical isolates of L. viridis were practically identical to each other except for some minor size differences.

Eating habits associated with Echinostoma malayanum infections in the Philippines.

A survey of 61 residents belonging to 12 pre-selected families (having at least one member positive for echinostomiasis malayanum) from Barangay Malibago, Echague, Isabela (northern Luzon) suggested that infections with Echinostoma malayanum follow a "familial trend". The parasite is endemic because the raw ingestion of Lymnaea (Bullastra) cumingiana, the second intermediate host in the Philippines, is a learned habit passed down from one generation to the next. A questionnaire on eating habits revealed that Lymnaea (Bullastra) cumingiana or "birabid" was usually prepared raw or half-cooked after treatment with salt or "bagoong" (salted fish paste). It was abundant in rice fields during the wet months of the year, thus implying a seasonal infection pattern since eating frequency was affected by availability. Those who ate this snail reported a long duration of indulgence with this habit. In contrast, Pila luzonica or "kuhol", the second intermediate host of E. ilocanum, is subjected to similar eating practices but is rarely ingested raw or "half-cooked". Other than snails, shrimps, fish (Tilapia sp.) and meat are also eaten raw. This suggests that the local population is potentially susceptible to other food-borne helminthiases. Extensive use of mass media and public health education is necessary to awaken the awareness of the people to the potential hazards associated with their traditional eating habits.

Factors affecting laboratory acclimatization of field collected Lymnaea (Bullastra) cumingiana Pfeiffer (Pulmonata: Lymnaeidae).

Lymnaea (Bullastra) cumingiana, the newly discovered natural second intermediate host of Echinostoma malayanum in the Philippines, is a sensitive and delicate lymnaeid species which requires certain conditions for successful transport from the field and cultivation in the laboratory. Field collected specimens were found to be best transported in styrofoam containers lined with wet filter paper or containing natural substrate and vegetation instead of Sphagnum moss. The method is convenient and produces a survival rate of 73-86%. However, transport time is crucial and mortality increases the longer the snails are in transit. For optimal results in laboratory acclimatization, snails are best raised in wide-mouthed containers providing a large exposed water surface area. Adequate aeration is advised but vigorous bubbling of the water should be avoided. Water should be replaced with filtered dechlorinated water every 2 to 3 days, depending on water quality. A combination of fresh lettuce leaves and a few flakes of fish food was found to be ideal. Lastly, population density was the most significant factor affecting survival and so overcrowding should be avoided.

Replacement patterns of Ascaris lumbricoides populations in Filipino children.

The replacement patterns of Ascaris lumbricoides worm populations were investigated by complete deworming of 150 Filipino children (0-14 years old) from both urban and rural barangays and analyzing the age distribution of the 2,072 adult worms (939 males and 1,133 females) obtained, based on Seo's (1983) regression equation relating length to age. It was observed that most worm populations followed a periodic pattern of replenishment. This supports the general practice of periodic anthelminthic campaigns. However, there seems to be a tendency for moderate and heavy cases to follow a continuous replacement pattern as evidenced by shorter time intervals between generations and wider age ranges. The data suggest that periodic deworming schedules may not be appropriate in areas where cases are predominantly of higher intensity. In such situations, control and/or eradication can probably be achieved only if chemotherapy is applied more frequently and supplementary health education and environmental modification measures are provided.

A comparison of the role of Musca domestica (Linnaeus) and Chrysomya megacephala (Fabricius) as mechanical vectors of helminthic parasites in a typical slum area of Metropolitan Manila.

A total of 1,016 flies (508 each for Musca domestica and Chrysomya megacephala) were collected from a typical urban slum area (Barangay 51, Pasay City, Metropolitan Manila) in the Philippines and examined for the presence of helminth ova attached to their external surfaces. A significantly greater proportion of C. megacephala (41.9%) was found positive compared to M. domestica (9.4%). C. megacephala also exhibited a significantly higher average egg load (11.9 eggs per positive fly) than M. domestica (2.6 eggs per positive fly). Male and female flies were equally contaminated for both species. Only 29 out of the 2,651 eggs recovered (1.1%) were infective to man. Ascaris spp. and Trichuris trichiura ova occurred most frequently while eggs of hookworm. Taenia spp., Toxocara spp. and Capillaria hepatica were infrequent or rare. Despite the low proportion of infective eggs recovered, the role of these synanthropic flies in the transmission of certain helminthiases should not be discounted.

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.

Lymnaea (Bullastra) cumingiana Pfeiffer (Pulmonata: Lymnaeidae): second intermediate host of Echinostoma malayanum in the Philippines.

Adult flukes were obtained from laboratory rats and hamsters fed with metacercariae isolated from Lymnaea (Bullastra) cumingiana Pfeiffer and were identified as Echinostoma malayanum Leiper based on the presence of a circumoral collar of 43-45 spines and the highly lobed testes. This discovery is of public health significance because L. (Bullastra) cumingiana in eaten raw by certain local populations in northern Luzon. The proposed new species, Cathaemasia cabrerai (Jueco and Monzon, 1984), is probably invalid because it apparently was based on E. malayanum flukes that had lost their circumoral collar of spines after treatment with praziquantel and bithionol. This is the first case where L. (Bullastra) cumingiana has been proven to be of medical importance in the Philippines. i.e., as the natural second intermediate host of E. malayanum. The first intermediate host and reservoir host of this parasite in the country are still unknown. Previously, only E. ilocanum was reported to be present in the Philippines.