These investigations were carried out in some of the villages around Taveta Town, Coast Province, Kenya, during the dry seasons of 1974, 1975 and 1976. The authors examined 83 wild rodents from villages where there is a high infection rate of S. mansoni and/or S. haematobium. The number and species of the rodents collected were as follows : 41

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Although 14 species of mosquitoes were collected in Che-ju Island, Korea in August and September, 1970-1972, dominant mosquitoes feeding on man around dwelling houses were Culex pipiens pallens and Aedes togoi. Natural infections with infective larvae of Brugia malayi were demonstrated only in Ae. togoi. It is considered from these facts that the main vector of malayan filariasis in Che-ju Island is Ae. togoi. Anopheles sinensis which is known as the vector of malayan filariasis in other areas does not seem to act an important role in the transmission in Che-ju Island, because the desnity is very low owing to the scarcity of suitable breeding places. The period for the larvae of Brugia malayi to mature in Ae. togoi was estimated to be between 6 and 9 days from the results obtained by dissecting the females of the mosquito reared in the laboratory for various days after the collection at houses with microfilarial carriers. This period is much shorter than in the case of Wuchereria bancrofti. The breeding of Ae. togoi was observed mainly in rock pools on the seacoast, and only very rarely in artificial water containers within villages. Generally, adult females of this mosquito were abundantly found at houses near to the seacoast, and the density decreased with the distance from the seacoast. Similar tendency was seen in the distribution of the patients of malayan filariasis. Che-ju Island, Korea, which is 1,820 km2 in area, is situated about 370 km southwest west to Tsushima Islands, Japan. In the center of the Island there is a mountain with an altitude of 1,950 m and the plain area is rather small so that rice fields are not much developed. Human filariasis caused by Brugia malayi is known to distribute densely in the Island, in which mosquitoes were studied in 1970, 1971 and 1972 in relation to malayan filariasis. The results obtained will be reported in this paper, as the second part of studies on malayan filariasis in Cheju Island, Korea.

Scanning electron microscopic observations have been made on the microfilariae of Brugia malayi and B. pahangi which already cast off their sheaths in vitro. The microfilariae of both species have striated appearances. B. malayi microfilaria varies in number of striations between 402 and 442 with an average of 423, and B. pahangi microfilaria between 443 and 485 with an average of 458. Except for the difference in number of striations, B. malayi presents close morphological resemblances to B. pahangi. The anterior end of the microfilaria forms the bluntly rounded cap provided with a wedgeshaped hook and two small pores. The hook measures 0.7-1.1 microns in length and projects backward. Of the two pores, one, rectangular in shape, exists at the center of the cephalic cap and the other, round in shape, lies between the base of the hook and the rectangular pore. Three fang-like spines are situated on the first annulus opposite to the hook side. The spines are equal in length, 0.6-0.7 micron, to one another. The spines usually point backwards, though they are occasionally directed forwards by the withdrawal of the cephalic cap into the cephalic space. The excretory pore lies on around the 150th annulus from the anterior end, but the opening of the anal pore has not been found in the present study. The tail tapers gradually showing striations, though near the end a few annuluses become expanded. The terminal appendage, connected to the last expanded annulus, is 6-7 microns long, club-shaped and striated.

Abstract:A total of 963 individuals in three villages were examined for schistosomiasis by both skin test and schistosome ova detection in stool and urine in 1974. The antigen used for skin test was VBS adult S. japonicum antigen (1 : 10,000 dilution). Stool and urine samples were examined through the concentration methods. Egg-positive rate was 62.2 per cent in Jipe, 68.0 per cent in Eldoro, 69.6 per cent in Kivalwa. Jipe was infested mostly by S. mansoni, Kivalwa by S. haematobium and Eldoro by both two schistosomes. The egg-positive rate was higher in females than in males in Eldoro. In Jipe and Kivalwa, however, the differences in the rate between males and females were not statistically significant. The rate increased with age in children, reached a peak between the ages of 5 and 14 years and then decreased gradually. The positive rate of skin test was 76.4 per cent in total, higher than that of stool and urine examinations. The skin reaction was weak or absent among many egg-positive children. The skin-testpositive rate increased as the age advanced and reached 95 per cent in inhabitants from 40 years up. The positive rate of skin test was higher among males than females in Jipe. No significant difference in the rate between males and females was found in Eldoro and Kivalwa. Among the egg-positive subjects there was no significant difference in skin reaction between S. mansoni infection and S. haematobium infection. In 1975 stool and urine samples from Jipe, Kivalwa, Kuwahoma and Chala were examined. Kuwahoma proved to be infested by S. haematobium. In Chala schistosome infection was rare. There exist villages infested by S. mansoni and/or S. haematobium in the small area. It seems that VBS adult S. japonicum antigen for skin test and the concentration methods for stool and urine examinations are of use in the epidemiological survey in the areas where S. mansoni and/or S. haematobium infections are prevailing.