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Biomedical subjects

J H Cross

Publications and source records attributed to J H Cross.

At least 127 records · Page 7Linked to original sources

Intestinal parasites of man in Northern Bohol, Philippines, with emphasis on schistosomiasis.

A survey for intestinal parasites with emphasis on Oriental schistosomiasis was conducted in the townships of Trinidad and Talibon, Bohol Province, Philippines and approximately 1,700 stool samples were examined. Schistosoma japonicum is still endemic to these areas of northern Bohol but infection rates were much lower than expected, 5% rather than 30%. Soil-transmitted helminths were the most common parasitic infections. Hookworms were found in 71% of the samples tested, most infections were due to Necator americanus 97% and Ancylostoma duodenale accounted for only 3%. Trichuris trichiura and Ascaris lumbricoides eggs were diagnosed in 58% and 45% respectively of the fecal samples examined. Other helminths and protozoan parasites detected were Enterobius vermicularis, Stronglyoides stercoralis, Entamoeba histolytica, Entamoeba hartmanni, Entamoeba coli, Endolimax nana, Iodamoeba bütschlii, Giardia lamblia and Chilomastix mesnili.

Adolescent↗

Additional isolations of Japanese encephalitis virus from the Philippines.

Japanese encephalitis virus was isolated from Culex tritaeniorhynchus, Culex bitaenorhynchus and Anopheles annularis mosquitoes collected from San Jose, Nueva Ecija, South Central Luzon in the Philippines. This is the second report of the isolation of the virus from mosquitoes in the Philippine Islands.

Animals↗

Lymphocyte response in mice infected with the Indonesian and Formosan strains of Schistosoma japonicum to concanavalin A, and to worm and egg antigens.

Cultures of splenocytes from mice infected with the Formosan and Indonesian strains of Schistosoma japonicum demonstrated a blastogenic response to concanavalin A (Con-A), adult worm antigen (SAA) and soluble egg antigen (SEA). The incorporation of tritiated thymidine was significantly greater for lymphocytes from mice infected with the pathogenic Indonesian strain than for lymphocytes from mice infected with the non-pathogenic Formosan strain in response to SAA; the responses also increased with duration of infection. The response to SEA, however, was only greater for the Indonesian strain, than that for the Formosan strain, at six weeks and the differences in response not statistically significant at five, seven, and nine weeks post-infection. The differences may have been associated with the number of worms developing in the mice since the adult worm recovery for the Indonesian strain was nearly twice that of recoveries from mice infected with the Formosan strain.

Animals↗

Susceptibility of new Taiwan foci of Oncomelania hupensis to geographic strains of Schistosoma japonicum.

Six new recently identified Taiwan Oncomelania hupensis foci were exposed to miracidia from the Changhua Taiwan zoophilic and Indonesian and Philippine anthropophilic strains of Schistosoma japonicum. All new foci were found susceptible to infection in varying degrees. In general the new foci were more susceptible to the Changhua zoophilic strain of S. japonicum than the anthropophilic strains; 17% exposed to the zoophilic strain shed cercariae while 9% and 7%, respectively, of those exposed to the Indonesian and Philippine human strains demonstrated infection. These snails along with O.h. chiui on Taiwan could possibly serve as intermediate host for human oriental schistosomiasis if the parasite was accidentally introduced onto Taiwan.

Animals↗

Travelers' diarrhea among U.S. Army troops in South Korea.

A prospective study of diarrhea was conducted among 98 U.S. Army soldiers during their first six weeks in South Korea. Diarrhea developed in 54 (55%) of 98 soldiers and had a mean duration of five days. Infections with Salmonella, Shigella, Vibrio, enterotoxigenic Escherichia coli, enteroviruses, and intestinal parasites were uncommon. Four (8%) of 50 soldiers with documented diarrhea, two (6%) or 32 with a history of diarrhea, and one (3%) of 29 who denied gastrointestinal symptoms had serologic evidence of a recent rotavirus infection. The etiology of diarrhea among U.S. soldiers who had recently arrived in South Korea differed from the etiology among travelers in warmer climates, where enterotoxigenic strains of E. coli were responsible for the majority of cases. Further efforts are needed to define other enteric pathogens in the etiology of diarrhea among new arrivals in different parts of the world.

Diarrhea↗

Etiology of gastroenteritis among Americans living in the Philippines.

Between December 1975 and June 1976, American military personnel with diarrhea who were seen at an outpatient clinic at Clark Air Force Base Hospital were investigated to determine the etiology of their disease. Enterotoxigenic Escherichia coli were detected in 16% (18/115), rotavirus in 4% (4/111), salmonellae in 3% (3/115), shigellae in 2% (2/115) and Giardia lamblia in 2% (3/152) of patients with diarrhea. Thus from only 27% of the subjects studied were identifiable potential pathogenic agents found. The incidence of gastroenteritis increased in May and June with the increase in rainfall; however, there was no increase in the proportion of diarrhea caused by any of these identifiable enteric pathogens. Americans experienced a seasonal increase of diarrhea similar to that affecting the Philippine population in Manila. Enterotoxigenic E. coli was the most common identifiable enteric pathogen among Americans with diarrhea at Clark Air Force Base in the Philippines during the study, though even in these cases, it may not have been the agent responsible for their illness.

Adult↗

Experimental transmission of Wuchereria bancrofti to monkeys.

Infective larvae of Wuchereria bancrofti from laboratory-raised Culex pipiens fatigans and Aedes togoi mosquitoes fed on human volunteers in Jakarta, Indonesia (J strain) and Kinmen Island, China (K strain) were introduced into Taiwan monkeys (Macaca cyclopis) by subcutaneous inoculation, by foot puncture, or by permitting infected mosquitoes to feed weekly on the monkeys. Some animals were splenectomized and others were treated with varying regimens of immunosuppressants. Necropsy was done on monkeys that died or were killed and the entire bodies were examined for worms. A total of 78 monkeys (43 males and 35 females) were exposed to infection and parasites were found in 29% of the females and 63% of males. In infections of 38 days or less worms were recovered from the testes of males and the pelt, carcass and lymph nodes of both sexes, but after 42 days of infection most worms were in the testes of males, and a few were recovered from lymph nodes and carcasses of females. Worms recovered at 8-11 days were third-stage, those found between 14 and 38 days fourth-stage, and ones found between 42 and 103 days were young adults. After 148 days most were adults and microfilariae were seen in the uteri of female worms at 160 days and later. The parasites continued to grow in size with time. Microfilariae were detected in the blood of nine monkeys between 8 and 18 months and the patent period varied from 5-21 months. Microfilarial densities were low and erratic, and periodicity could not be determined. The effectiveness of methods of administering infections and the value of various treatment regimens seem uncertain; monkey antilymphocytic sera, however, appeared to have some influence. Parasites were found in 36% of the Taiwan monkeys given the J strain and 54% of those given the K strain. A limited number of M. mulatta (3), M.irus (fascicularis) (3) and Aotus trivirgatus (4) were also given infective larvae and adult W. bancrofti were recovered from the testes of one male M. mulatta and one male M. irus; uterine microfilariae were found in one female worm from the latter monkey. A. trivirgatus were negative. Low numbers of infective larvae recovered from mosquitoes fed on patent monkeys were introduced intermittently into seven clean monkeys and one became microfilaremic between 11 and 17 months postinoculation.

Aedes↗

Antigenic analyses of two axenized strains of Entamoeba histolytica by two-dimensional immunoelectrophoresis.

Antigens in extracts of two strains of Entamoeba histolytica (HT-31 and HK-9) were studied by two-dimensional immunoelectrophoresis (2D-IEP) and 32 and 20 different antigenic components were detected, respectively. Cross-reactions between heterologous systems showed a large number of shared antigens between the two strains. Extracts were fractionated by Sephadex G-200 chromatography. Of the fractions obtained, fraction II of both strains was found to have the most reactive antigenic components. Precipitin patterns of fraction II from HT-31 and HK-9 with sera from patients showed similar 2D-IEP profiles and suggested that in this fraction antigens common to both strains exist which elicit antibody in individuals with E. histolytica infections.

Animals↗

Transovarial transmission of Japanese encephalitis virus by mosquitoes.

Female Aedes albopictus and Aedes togoi mosquitoes infected with Japanese encephalitis virus either by intrathoracic inoculation or by ingestion of a virus-sucrose-erythrocyte mixture transmitted the virus to a small percentage of their F1 progeny. Adult F1 female Aedes albopictus thus infected transmitted the virus in turn to newly hatched chickens by feeding on them.

Aedes↗

Reovirus-like agent and enterotoxigenic Escherichia coli infections in pediatric diarrhea in the Philippines.

Of 82 children hospitalized with diarrhea in the Philippines during January-June 1976, 14 (17%) had infections due to a reovirus-like agent as determined by detection of viral particles in stools by electron microscopy (12 [15%] of 82) and/or by a rise in titer of antibody to the serologically related Nebraska calf diarrhea virus (eight [20%] of 39). Escherichia coli producing heat-labile enterotoxin were found in six (7%) of 82 ill children and two (4%) of 49 healthy control children, while E. coli producing heat-stable enterotoxin were isolated from three children with diarrhea and two without gastroenteritis. Thirty-eight percent of enterotoxigenic E. coli isolated from children with diarrhea, but only 6% of isolates from healthy control, were of serotypes similar to those of enterotoxigenic E. coli isolated in previous studies of these pathogens by other investigators in geographically diverse areas (serotypes O6:H16, O8:H9, and O78:H12) (P less than 0.05). Eight (10%) of the children had infections with multiple enteric pathogens.

Antibodies, Bacterial↗

Counterimmunoelectrophoresis in the detection of antibodies to Schistosoma japonicum.

Counterimmunoelectrophoresis (CIE) was used to detect antibodies to Schistosoma japonicum soluble egg antigen in 118 sera from people living in a schistosomiasis endemic area in the Philippines. The sera were also tested for antibodies by the circumoval precipitin test (COPT); 53% were found positive by CIE and 48% positive by COPT. No significant differences were found between the tests (P = 0.18 by McNemar's test). Cross-reactions with sera from patients with intestinal capillariasis and monkeys with experimental angiostrongyliasis were not found and no false reactions were detected with sera from "normal" controls. The CIE test as used in the present studies was found to be comparable to the COPT in sensitivity and specificity as related to cross-reactivity with sera from nematode infections such as intestinal capillariasis and angiostrongyliasis. Results are usually available quickly with nearly 70% of any reactions occurring within 1 h. The test should be of value in seroepidemiologic surveys in schistosomiasis-endemic areas.

Adolescent↗

Travelers' diarrhea among United States Marines in South Korea.

A battalion of United States Marines traveling to South Korea in the spring of 1976 was studied to determine the incidence and etiology of gastroenteritis. During the three weeks they visited South Korea, 21% of 694 marines developed diarrhea. Stool and serum specimens collected before, during, and after their stay were examined for evidence of infection with Salmonella, Shigella, and Vibrio species, enterotoxigenic and invasive Escherichia coli, reovirus-like agent (RVLA), and intestinal ova and parasites. Infections with these agents were uncommon; 91% of 44 closely studied cases of gastorenteritis were unexplained. Five per cent of 169 marines had serologic evidence of recent infection with RVLA, and 3% of 273 marines had serologic evidence of infection with heat-labile enterotoxin producing E. coli over an eight-week period. However, infections with these agents were not associated with most cases of diarrhea in South Korea. It is concluded that infectious agents previously thought responsible for travelers' diarrhea were not responsible for gastroenteritis among United States Marines arriving in a temperate climate.

Diarrhea↗

Human filariae in Indonesia.

The distribution of human filariae in Indonesia has not changed significantly since initial reports of the disease were made in 1928. Wuchereria bancrofti and Brugia malayi are widely distributed but the newly described Brugia timori appears to be restricted to the Lesser Sunda Islands. W. bancrofti and B. timori in Indonesia are nocturnally periodic and B. malayi has nocturnally periodic and B. malayi has nocturnally periodic and nocturnally subperiodic strains.

Brugia↗

Serum immunoglobulin levels in Indonesians with bancroftian filariasis.

Serum immunoglobulin (Ig) levels (IgA, IgM, IgG, IgE) were determined on 185 Indonesians mostly males with and without microfilaremia and with and without clinical disease (hydrocele and elphantiasis). No significant differences were found in IgA and IgE levels in any of the groups but significantly higher IgG levels were found in microfilariae positive persons than those without microfilaremia. Persons with microfilariae alone and symptoms alone, but not both, had higher levels of IgM. There were no correlations between disease category and Ig levels.

Adolescent↗