SCHISTOSOMIASIS 227 
lateral-spined ova of S. mansoni in the faeces, with disturbances of the rectal 
mucosa and intestine. In only one case was S. haematobium found in the faeces 
and in only one was S. mansoni found in the urine. However, in parts of the 
central Belgian Congo about Stanleyville the ova found in the faeces in several 
intestinal cases of infection possessed a terminal spine. 
Chesterman ! has pointed out that at Yakusu, near Stanleyville, intestinal 
bilharziasis is the only form of the disease which occurs and that the cases 
show terminal-spined eggs somewhat more elongated than those typical of 
S. haematobium. He also pointed out that the local intermediary host is very 
like, if not identical with, Bullinus contortus.2. (See also No. 174.) 
Blacklock * examined the urine of 668 cases in Sierra Leone for S. haemato- 
bium infection and found ova in 215 of the cases. Examination of the faeces 
proved negative with one exception, in a woman, where the terminal-spined 
ova of S. haematobium were found. 
Leiper * in commenting upon this rare occurrence of the ova of S. haemato- 
biwm in the faeces (which experience corresponded with our own in Liberia), 
says that in Egypt the eggs are fairly common in the faeces. Leger and Bédier °* 
examined 127 natives at Dakar and found that 6.8 per cent of them passed 
ova of S. haematobium in the urine. However, no eggs were found in the 
faeces of any of these cases. 
On the other hand, Nessman and Trensz* have recorded three cases of 
rectal infection with S. haematobium in Gabon, French West Africa, and refer 
to the absence of indications of vesical implication. They believe that such 
cases are more frequent in this region. 
Khalil’ in other parts of Africa points out that double infection of the 
urinary and intestinal tracts with the species of Schistosoma, S. haematobium 
and S. mansoni, is by no means rare. Of 7,090 individuals who were examined, 
56 had S. mansoni eggs in the urine and of these 48 had a urinary infection 
with both parasites, while eight had S. mansoni alone. Fairbairn ® and Cole- 
man ° have also reported double infection with S. haematobium and S. mansoni 
in cases of vesical bilharziasis. Leger and Raynal?? have recently studied 
instances of aberrant localization of Schistosoma ova and find them difficult to 
explain. Two hypotheses have been suggested by Leger, one to the effect that 
we may be dealing with a new form of bilharziasis and a second based on the 
assumption that a special intermediary host such as a particular gastropod in 
certain regions might be capable of modifying the tropism of the schistosomes. 
The aberrant localizations of the ova of the schistosomes appear to be encoun- 
1 Chesterman: Ann. Soc. Belge de Méd. Trop., Brux. (1923), III, 73. 
2 Bequaert, however, has identified these specimens of this snail as Physopsis africana. (Bull. 
Amer. Museum Natural History [1927], LIII, 145). 
3 Blacklock: Trans. Soe. Trop. Med. and Hyg. (1925), XVIII, 406. 
4 Leiper: Jbid., 420. 
5 Leger and Bédier: Bull. Soc. Path. Exot. (1923), XVI, 276. 
6 Nessman and Trensz: Ann. Parasit. Humaine et Comparée (1928), VI, 182. 
7 Khalil: Brit. Med. Jour. (1928), p. 546. 
8 Fairbairn: Brit. Med. Jour. (1928), p. 52. 
9 Coleman: Jbid., p. 177. 
10 Leger and Raynal: Corr. from Paris, Jour. Amer. Med. Assoc. (1929), XCIII, 1157. 
