Presence of ketones in the serum of Trypanosoma evansi infected camels (Camelus dromedarius) in the Sudan

In order to define the eventual role of small ruminants in the epidemiology of T. evansi infection in Southern Mauritania, the following exepriments were carried out : the intravenous inoculation of a ewe and a goat with a local strain of T. evansi isolated from a dairy came1 ; surveys of small ruminant flocks which graze with infected camels in the South of the Trarza region. The experimental inoculation allowed to show that local sheep and goats are receptive. Only the ewe showed a clinical episode with loss of weight and abortion. During 220 days after inoculation the blood of the goat remained constantly infectious for the mouse whereas in the same period the ewe’s blood showed an alternation of infectious and non-infectious phases. However in the field, none of 381 blood smears of small ruminants (207 goats, 174 sheep) were positive and none of the 187 serums (109 goats, 78 sheep). Therefore, it seems that the small ruminants of the South Mauritania do not play any role in the epidemiology of T. evansi came1 trypanosomosis even if they are receptive to experimental inoculation.

In order to define the eventual role of small ruminants in the epidemiology of T. evansi infection in Southern Mauritania, the following exepriments were carried out : the intravenous inoculation of a ewe and a goat with a local strain of T. evansi isolated from a dairy came1 ; surveys of small ruminant flocks which graze with infected camels in the South of the Trarza region. The experimental inoculation allowed to show that local sheep and goats are receptive. Only the ewe showed a clinical episode with loss of weight and abortion. During 220 days after inoculation the blood of the goat remained constantly infectious for the mouse whereas in the same period the ewe's blood showed an alternation of infectious and non-infectious phases. However in the field, none of 381 blood smears of small ruminants (207 goats, 174 sheep) were positive and none of the 187 serums (109 goats, 78 sheep). Therefore, it seems that the small ruminants of the South Mauritania do not play any role in the epidemiology of T. evansi came1 trypanosomosis even if they are receptive to experimental inoculation.

Introduction
Came1 owners in Eastern Sudan claim that in came1 trypanosomes are associated with a characteristic pungent odour of the urine, just like the smell of bad water melon. HUNTER (2) detected a small amount of ketones in the urine of T. evansi positive camels. In the present study serum and urine samples were used for further elucidation of this feature.

Materials and Methods
Hundred blood samples were collected from the jugular vein at the Veterinary clinic or from different localities 1 around Kassala town during the year 1990-1991. Blood i was collected in vaccutainers containing EDTA and plain i , vaccutainers for serum separation.
Sera were kept at -20°C until used. From each blood sample, wet film, thin smear and buffy coat (PCV) prepa-~ ~ rations were examined for detection of trypanosomes.
All I sera were examined by the mercuric chloride test. One ~ gram of mercuric chloride was dissolved in 250 ml of dis-~ tilled water; 5 ml from this solution was made up to 500 ml with distilled water. One ml of this solution was put into each of two test tubes, and 20 PI of serum was added to one'test tube and the other was left as a control. White turbidity indicated a positive reaction. According to these examinations, the sera were divided into three groups. In group 1, the trypanosomes and mercuric chlori-: . Three grams of sodium nitroprusside were mixed with 100 g of ammonium sulphate and 50 g of anhydrous sodium carbonate. An amount of 0.1 g of this powder was put on a white porcelain tile, 40 pl of serum or urine were added and observed for 5 min. to detect any change of colour. Violet colour indicated a positive reaction. No change in colour indicated a negative reaction (absence of ketones). All serum groups 1, II and III were tested in this way.

Results
Results are presented in table 1. It was observed that the velocity and intensity of colour formation were propor-tional to the putative ketone concentration present in the serum. In group 1, the colour changed rapidly to intense violet within one minute. In group II, a faint colour was observed within two to three minutes, whereas in group III, no change was observed even after five minutes.

Discussion and Conclusion
Earlier studies with the "humoral" group of trypanosomes ascribed death of the host to a progressive and terminally fatal hypoglycaemia, caused by high carbohydrate consumption of the parasite (4). This may explain our findings of ketones in the serum of trypanosome infected camels. Ketone bodies are referred to as acetoacetate, B-OH-butyrate and acetone. Because nitroprusside does not react with B-OH-butyrate, the ketone bodies found could be either acetoacetate, acetone or both.
Despite the small number of urine samples taken from trypanosome-infected camels, we believe that the presente of ketones in the urine was due to the resultant increase in blood levels (1). The faint reaction observed in group II needs fur-ther investigation.
Thus, it could be concluded that ketone bodies are found in the serum of trypanosome infected camels and that the pungent odour of the urine could be attributed to their presence.