1698 



TROPICAL POISONINGS 



ONYALAI. 



Synonyms. — Edyuo (Biikoba); Kafindo (Congo). 



Definition. — An acute disease of unknown causation, characterized 

 by the appearance of bullae containing blood on the surface of the 

 body, the tongue, soft palate, or buccal mucous membrane. 



History.— The disease was discovered by Yale Massey in Angola 

 in 1904, and fully described by Wellman later in the same year in 

 Portuguese West Africa, and by Feldman, in 1905, in East Africa, 

 where it is called ' ed3^uo ' by the natives of Bukoba. Mense (1906) , 

 thinks that the ' kahndo ' disease of the Unyamwezi people of the 

 Congo is the same disease. Hsemorrhagic bullce in the mouth, but 

 without general symptoms, have been described by Maxwell in 

 Changpo, South China, as being due to the accidental introduction ^ 

 into the mouth of a kind of spider's web. 



|>ffitiology. — This is unknown, but Mense thinks it may be some 

 kind of poisoning, perhaps with some species of the Euphorbiacese. 

 Wellman considers that it is not a manifestation of malaria; nor 

 is it a vegetal poisoning, nor a snake-poisoning, though the bite 

 of Bitis arietans, the puff-adder, simulates some cases closeJy. 

 Neither trypanosomes nor bacteria were found. It is not a pur- 

 pura hsemorrhagica, nor Henoch's purpura, nor Schonlein's disease. 



Symptoms. — The onset is sudden, and is accompanied by lassitude 

 and a dazed appearance. Sometimes the parotids are tender, and 

 the eyes may be somewhat reddened, and in about 66 per cent, of 

 cases there is a slight rise of temperature. Numbness and pain in 

 various parts of the body may be noted. 



The appetite is poor; bullae may be seen on the tongue and in 

 the mouth and pharynx, while they also occur in the oesophagus, 

 stomach, and bowels. The tongue is swollen and painful. Vomit- 

 ing of blood is not rare, and bloody diarrhoea may take place. 

 Haematuria has been noted, and cerebral haemorrhage, with the 

 usual signs, has been seen. It is believed that haemorrhage into 

 the pancreas, liver, and spleen, may take place in some cases. 

 Bullae may also appear in the skin, ranging from the size of a split 

 pea to several inches in diameter. The typical bullae, whether on 

 a mucosa or in the skin, extend deeply, involving the submucosa 

 or the corium, and are crossed by fibrous trabeculae, in the meshes 

 of which lies partially coagulated blood, which appears dark 

 through the skin or mucosa. The red corpuscles are not disin- 

 tegrated, and can be seen by the microscope. 



The disease is said to have a tendency to recur two or three 

 times. 



Diagnosis. — The diagnosis from snake-bite may be effected only by 

 the history, as the bullae may not be visible on the skin or mucosa. 

 Malaria can be excluded by the blood examination. Schonlein's 

 disease, or peliosis, is diagnosed by the rash, painful swelhng of 

 the joints, and the purpuric eruption. Henoch's purpura is met 

 with generally in children, and has joint symptoms as well as a rash. 



