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Biomedical subjects

P C Fan

Publications and source records attributed to P C Fan.

At least 91 records · Page 5Linked to original sources
PubMed1989

A study on enterobiasis among aboriginal children in Nanao and Tatung districts, Ilan county, northeast Taiwan.

From May 1981 to March 1984, consecutive surveys with Scotch tape perianal swab for enterobiasis were conducted among school children in 8 primary schools in the Nanao District, also involved were 1 junior high and 8 primary schools from the Tatung District, Ilan County, Northeast Taiwan. Field treatments with mebendazole (10 mg) or albendazole (400 mg) were also conducted following 9 periods of screening for pinworm. Prior to treatment, the infection rates in Nanao and Tatung were 14.1% and 8.3%, respectively. These rates were reduced to 0.4% and 1.1% by March 1984, respectively. Throughout the study, significantly higher infection rates were generally found during the months of September, November, and December and lower rates were obtained in June. There was no difference between the infection rates of aboriginal school boys and girls. The results of the present study indicate that monthly chemotherapy is the best method for controlling pinworm infections in these mountainous regions.

Adolescent↗
PubMed1988

Taiwan taenia and taeniasis.

Toeniids are large tapeworms, common throughout the world. Two species, Taenia saginata and T. solium are common parasites of man. The adult worms parasitize the small intestine, while immature stages (metacestodes or cysticerci) develop mainly in cattle in the case of T. saginata or pigs in the case of T. solium. Cysticerci of T. saginata rarely develop in man, although humans are easily infected with those of T. solium after eating raw or undercooked infected pork-producing the disease known as cysticercosis. In Taiwan, both the pork and beef tapeworms have been documented among aboriginal peoples - with T. saginata considered the most prevalent species. But, as P.C. Fan discusses here, the 'Taiwan Taenia' has several unusual features - not least the fact that beef is not part of the traditional diet of Taiwan oboriginols.

Journal Article↗
PubMed1988

Experimental infection in a human subject by a possibly undescribed species of Taenia in Taiwan.

A cysticercus of a possibly undescribed species of Taenia which occurs commonly in Taiwan aborigines was used to establish an experimental infection in a human volunteer. Symptomatic effects attributed to the infection included diarrhoea, upper abdominal pain, and increase or loss of appetite over a four-month period. After an expelled proglottid was observed 122 days post-exposure, eggs and proglottids were found continuously until the patient was treated with anthelmintics. Antibody titres measured by enzyme-linked immunosorbent assay and levels of eosinophilia seemed to correlate with symptoms. Haematological analyses revealed an abnormal lipid metabolism during the entire symptomatic period.

Adult↗
PubMed1988

An outbreak of schistosomiasis japonica in Taiwan.

The present study was undertaken to determine the current status of Schistosoma japonicum infection in the newly found endemic focus at Hanpao Farm, Fangyuan District, Changhua County, West-Central Taiwan. Two field surveys and one laboratory investigation were conducted from July to October 1987. Of 705 snails examined by shedding and crushing methods, 17.0% were found to harbor cercariae of S. japonicum. By sodium sulfate-acid-ether-triton centrifugal sedimentation technique, 25% of 16 cattle, 40% of 5 goats, and 50% of 4 dogs were found to be positive for S. japonicum eggs. In the laboratory, 21 mice were exposed to cercariae from single naturally infected snails. Following inoculation, 7 mice died early, 7 were found infected with male worms, 2 with female worms, and 1 with bisexual infection. The results of the present study indicated that the infection rates of snails and domestic animals are higher than those previously reported from elsewhere in Changhua County.

Animals↗
PubMed1987

Laboratory transmission of lymphatic filariasis by vector mosquitoes.

Aedes togoi and Ae. aegypti were used to examine the transmission potential of Brugia pahangi to one of its natural hosts, the domestic cat. Although a larger proportion of microfilariae taken in by Ae. togoi developed into infective larvae, the total number of B. pahangi larvae recovered from a cat exposed to Ae. aegypti was larger than from a cat exposed to Ae. togoi. Factors influencing the transmission dynamics included: development of microfilariae to infective larvae; survival of mosquitoes; willingness to take repeated blood meals; and proportion of infective larvae that egress from mosquitoes during the feeding process. From 19 to 25% of infective larvae were transferred to a susceptible host. The feasibility of using a Brugia-cat model to do comparative vector efficiency studies was demonstrated.

Aedes↗
PubMed1986

Studies on taeniasis in Taiwan. V. Field trial on evaluation of therapeutic efficacy of mebendazole and praziquantel against taeniasis.

Taeniasis is a major public health problem among the aboriginal populations on Taiwan, and is highly prevalent and wide spread in the mountain areas of 10 Counties. Over 27,000 cases of tapeworm infection are estimated influencing the health and economy in the endemic areas. A treatment of taeniasis with mebendazole and praziquantel followed by a re-treatment with atabrine has been done in the field trial, and confirmed that praziquantel is highly effective agent against tapeworm infection, but mebendazole is not. Based upon experiments reported here praziquantel in a single dose of 150 mg, and 450 mg are highly effective against taeniasis and hymenolepiasis respectively.

Adolescent↗
PubMed1985

Experimental infection of subperiodic Brugia malayi in laboratory rats with emphasis on evaluation by four techniques.

Infective larvae of subperiodic B. malayi from South Kalimantan (Borneo), Indonesia collected from laboratory-raised Ae. togoi mosquitoes after feeding on infected mongolian gerbils (Meriones unguiculatus) were inoculated subcutaneously into the groin areas of 15 SD and 36 LE rats. Blood was examined weekly by membrane filtration and thick smears starting 10 weeks post-infection. Microfilariae were found in 3 SD and 4 LE rats, the mf infection rate of 20% and 11% respectively. The prepatent period was significantly shorter in the SD rats (99-112 days) than those in the LE rats (110-153 days). The patent period was longer in the LE rats (208-703 days) than in the SD rats (236-543 days), and the mf density was similar (17.5 mf/20 c.mm blood against 16 mf/20 c.mm blood). At necropsy, 6 (3 female and 3 male) adult worms were recovered from 3 of 6 SD rats and 12 (9 female and 3 male) adult worms from 4 of 20 LE rats; all worms were found in the testes. The results of xenodiagnostic, histochemical staining and measuring spicules and protuberances, demonstrated clearly the difference between both species of Brugia. All dissected Ar. subalbatus mosquitoes exposed to B. pahangi became infected (100%), but none of those to subperiodic B. malayi were infected (0%). The mf of both species of Brugia in thick films stained with naphthol-AS-TR-phosphate showed that the excretory and anal pores of subperiodic B. malayi mf exhibited acid phosphatase activity and only a little activity was seen in other parts; while B. pahangi mf showed heavy diffuse acid phosphatase activity along the entire length of the body.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Survey of helminthic infections and treatment of Taenia species infection among the aborigines in Chien-Shih District, Hsin-Chu County, northern Taiwan].

Six hundred and sixteen out of 770 (80%) aborigines examined were found to be infected with intestinal helminthes. A total of 7 species of parasites were detected with the formalin-ether concentration technique. The infection rate of Ascaris lumbricoides was 77.1%, Trichuris trichiura 28.8%, Taenia sp. 18.4%, Enterobius vermicularis 1.6%, and there was one case each of hookworm, Hymenolepis nana and H. diminuta infections. Infection rate was slightly higher among females (81.3%) than males (78.9%). It was also higher in Yu-Feng (86.9%) than Shiu-Luan villages (75.5%). The incidence of helminthic parasites was found in all ages. 11-20 age-group was the highest (84.4%), followed by 1-10 (81.5%), 51 and more (80.6%), 41-50 (77%), 31-40 (76%), and 21-30 (72%). In general, the rate seems to be higher among the young and old. But, the rate of Taenia sp. was increased with the increase in age. Taenia sp. was found to be of considerable high prevalence. However, only 7 out of the 252 (2.7%) junior high school students were found infected in contrast to the 18.4% found in the villages. After atabrine treatment, 108 adult worms, 83 with and 25 without scolices were obtained from 54 of 72 treated cases. The number of expelled worms varied from 1 to 8, with an average of 2 worms per infected person. 29 (53.7%) aborigines expelled only one worm, and 25 (46.3%) cases expelled more than one worms.

Adolescent↗
PubMed1985

Medically important snails of Kinmen (Quemoy) Islands.

A survey and collection of the snails of medical importance were conducted in June, 1980 on Kinmen Islands. More than 2,700 snails were collected from 23 different localities. They were preserved, carefully classified, and compared in habitat distribution with snails of Taiwan. A total of fourteen species of snails was found. This study has led to the establishment of snail fauna of Kinmen. The relationships of these snails with some snail-borne diseases are discussed.

Animals↗
PubMed1984

[Preliminary report on the susceptibility of mosquitoes to Brugia pahangi].

A comparative study on the susceptibility of eight species of four genera of mosquitoes to Brugia pahangi was carried out. Aedes aegypti (Liverpool strain), Aedes togoi, Armigeres subalbatus and Mansonia uniformis (Taiwan strains) were found with the third-stage larvae 14 days after feeding on infected rats (Sprague-Dawley). The remaining of Aedes aegypti, Aedes albopictus, Aedes pseudoalbopictus, Culex p. fatigans and Culex annutus (Taiwan strains) were found refractory to infection. To determine the infectivity of the four susceptible species, the mosquitoes were fed on the same rat (mf. density 70/20 cmm blood). They were dissected and examined 14 days later. Significantly higher numbers of infective-stage larvae per infected mosquito were found in Armigeres subalbatus (42.6), Aedes togoi (8.8), Aedes aegypti (Liverpool strain) (7.6) and Mansonia uniformis (3.3).

Animals↗
PubMed1983

The effect of a phase transition on penetration of phospholipid monolayers by melittin and glucagon.

The penetration of melittin and glucagon into phospholipid monolayers was studied by measuring compression isotherms of phospholipids in the absence and presence of various concentrations of protein in the subphase. Differences in molecular area were calculated as a function of protein concentration at constant pressure. Area change as a function of surface pressure at constant protein concentration was also calculated. Melittin showed greater affinity for penetration into phosphatidylglycerol (PG) than into phosphatidylcholine (PC) monolayers. The cutoff pressure for melittin penetration was 45 mN/m with PC and 60 mN/m (extrapolated) with PG. Dipalmitoyl PC and PG monolayers show phase transitions upon compression at 25 degrees C. Both melittin and glucagon showed increased penetration as measured by area change within the region of the phase transition with both lipids. Glucagon showed a cutoff pressure of 25 mN/m for penetration into dimyristoyl PC. The preference of glucagon for interaction with lipid bilayers in the gel phase is discussed with respect to monolayer penetration as a function of surface pressure.

Bee Venoms↗
PubMed1982

Further studies on the susceptibility of new Taiwan foci of Oncomelania hupensis to geographic strains of Schistosoma japonicum.

Two known colonies of O.h chiui in Alilao and of O.h. formosana in Changhua and four new foci of snails in Nantou, Chiayi, Hualien and Taitung on Taiwan were exposed each to 5 miracidia of Changhua Zoophilic strain and Chinese, Philippine and Indonesian anthropopilic or human strains of S. Japonicum. The results showed that all four new foci demonstrated various degrees of susceptibility to this parasite. Infectivity of Chinese strain of S. japonicum in 4 new foci of snails is reported for the first time. Changhua race of O. hupensis was also found slightly susceptible to Chinese strain of the parasite. The average infection rate to both zoophilic and human strains of S. japonicum was 39.0%, 14.5%, 10.8% and 9.8% for Taitung, Chiayi, Hualien and Nantou snails respectively. Susceptible snails now been found in 7 counties and if by chance human pathogenic strains of the parasite were accidentally introduced into Taiwan, a public health problem could possibly develop.

Animals↗
PubMed1982

Studies on the susceptibility of new Taiwan foci of Oncomelania hupensis to Ilan and Japanese strains of Schistosoma japonicum.

Sixty snails from four new foci of O. hupensis in Taitung, Chiayi, Hualien and Nantou counties, and 4 known colonies of O. h. chiui in Alilao and Pali in Taipei as well as of O. h. formosana in Changhua and Ilan on Taiwan were exposed each to 5 miracidia of Ilan zoophilic strain and Japanese anthropophilic or human strain of S. japonicum. This is the first report to note that all four new foci of O. hupensis snails were highly susceptible to Ilan strain of S. japonicum (17-20%). Susceptibility to the Japanese strain was detected in Taitung (33%), but, very low to not susceptible for the Hualien (2%), Chiayi and Nantou snails. Susceptibility of new Taiwan foci to the geographic strains of S. japonicum has now been well established, widespread distribution of susceptible snails in Taiwan could possibly lead to public health problem in the event that S. japonicum were introduced to the island.

Animals↗
PubMed1981

Prevalence of Pediculus humanus capitis among school girls of Chuang-Wei and Nan-Ao Districts in I-Lan County and Man-Chow District in Ping-Tung County, Taiwan.

By using the naked eye examination and comb method, a field survey and combing collection of head louse (Pediculus humanus capitis) among school girls in three different area (Man-Chow, Nan-Ao and Chuang-Wei) of Taiwan were performed from July 1979 to February, 1980. The general infestation rate of head louse was 39.8% (or 998/2,509). In the primary schools, comparatively, the rate at Man-Chow (66.7%) was highest, the next at Nan-Ao (55.4%) and the lowest at Chuang-Wei (39.4%). While in the junior high schools, the rate was apparently higher at Nan-Ao (38.4%) than that at Man-Chow (15.6%) and Chang-Wei (12.0%). The highest rate in the primary schools was found in 3rd graders except at Chuang-Wei in 5th graders. The corresponding figure in the junior high schools was found in 1st graders except at Nan-Ao in 2nd graders. Of 774 infested girls studied, according to the number of lice per infested girl, the percentages of infestation in the 5 groups were: the very light (nits only) 54.5, light (1-10) 38.5, moderate (11-50) 6.5, heavy (51-100) 0.4 and very heavy (over 100) 0.1 respectively. Of 2,178 head lice examined, 53.0% was nymphs; 28.7% females; 18.2% males. The average number of head louse in each infested girl 6.2.

Age Factors↗
PubMed1980

Experimental transmission of Trypanosoma gambiense by syringe passage from albino-mouse to mice, rats, gerbil and hamster.

In the present experiment, 10 laboratory rodents (1 gerbil, 1 hamster, 4 mice and 4 rats) were inoculated intraperitoneally each with a same number of 595,000 trypanosomes. The shortest period of prepatent in mouse (129/svsl) was found 6:30 hours post-inoculation; next in gerbil, rat (Long-evans) and mouse (C13H) at 7:40, 8:20 and 8:30 hours respectively. Then, a serial blood samples (1 cmm) were taken with a pipetman and examined at an intervals of 8 hours. It proved that all rodents were found susceptible to T. gambiense infection. The number of parasites was increased over one and half millions per 1 cmm of peripheral blood in all rodents. But the number was apparently low an irregular in gerbil and hamster. No trypanosomes was found within a period of 106 to 162 hours post-inoculation in hamster, then, the parasites re-appeared until death occurred. The survival of infected rodents was comparatively shorter in mice than that in rats. All rodents died within a period of 196 hours (or 8 days) except hamster living for 576 hours (or 24 days). Based on the above figures, it seems probably that the hamster may have the natural resistance and host's tolerance for T. gambiense infection. Therefore, hamster may be the most satisfactory and economical animal for maintenance of T. gambiense infection for experimental studies in laboratory.

Animals↗
PubMed1977

The effect of diethylcarbamazine treatment on the development of bancroftian microfilariae in Culex p. fatigans.

Bancroftian microfilarie survived after one to three courses of diethylcarbamazine treatment in carriers and the larvae able to reach the infective stage in Culex p. fatigans. The infection rate and the development of infective larvae per infected mosquito from DEC-treated carriers was much lower than from the untreated carrier. The fact that surving MF can develop to infective stage in their vector indicates that such filarial carriers may be important sources for transmission of filariasis in the endemic areas after suspension of control measures.

Adolescent↗