A cta Tropwa, 49(1991)233-236 Elsevier

233

ACTROP 00153

Cymelarsan in the treatment of buffaloes naturally infected with Trypanosoma evansi in South China Z.-R. Lun 1'*, Z.-P. Mm z, D. Huang 3, J.-X. Liang 2, X.-F. Yang 2 and Y.-T. Huang'* ~Parasttology Laboratory, Department of Bzology, Zhongshan Umverslty, Guangzhou, 2Guangxl Vetermarv Research Institute, Nanmng, ~Vetermary Station of Gao Yao Count)', Guangdong Provmce, ~Vetermary Stauon of Nannmg, Guangxt, People's Repubhc of Chma

(Recewed 21 December 1990, accepted 28 February 1991) Forty buffaloes naturally infected with Trypanosoma evansl in the South of China were treated with a singledose of a new arsenical, Cymelarsan (Mel Cy) at 0 25 mg/kg to 3 0 mg/kg by intramuscular rejection All ammals were cured, with the exception of two out of four ammals treated with 0 25 mg/kg Mel Cy which relapsed two months after drug administration Two out of eight buffaloes m control groups treated with a single dose of dimmazene aceturate (Berenil), 3 5 mg/kg, relapsed two months after treatment All cured ammals showed no trypanosomes in their blood when tested within one to three years after administration A scleroma about 2 to 3 5 cm in diameter was found at the site of rejection at the dose of 1 5 mg/kg Mel Cy in three of eight animals At a dose of 3 mg/kg, Mel Cy induced obvious necrosis of the tissue at the site of inJection The results of field apphcatlon proved that Mel Cy is a very active trypanocldal drug against T evanst Key words Trvpanosoma evanst, Buffalo, Chemotherapy. Cymelarsan, Berenll

Introduction Trypanosoma evanst, the cause o f surra disease has the w~dest geographical d~stnbutlon o f all the p a t h o g e m c t r y p a n o s o m e species. This parasite ~s one of the most e c o n o m i c a l l y i m p o r t a n t p a r a s m c p r o t o z o a It infects domestic a m m a l s such as camels, horses, buffalo a n d deer m the People's R e p u b h c of China, especially m the south (Peng, 1987), as well as cattle, goats a n d sheep m Africa (Lucklns, 1988). Buffaloes infected with T evans1 m C h i n a usually show depressed behavior, emacia t i o n a n d a n a e m i a The hmr becomes r o u g h a n d lustreless. There ~s h y p e r a e m l a o f the conjunctivae, lachrymat~on a n d b l e n n o p h t h a l m l a m the l n t r a - o r b l t a w~th a whitegrey exudate Some a m m a l s show necrosis at the edges o f the ears A l t h o u g h the refection becomes chromc, m o s t a m m a l s die if n o t treated Berenll (D~mlnazene aceturate) ~s the m o s t i m p o r t a n t d r u g used to treat a m m a l t r y p a n o s o m l a s l s m China. S u r a m m , Q u l n a p y r a m l n e (Antryclde) a n d I s o m e t a m l d m m ( S a m o r m ) are also used against T evanst, b u t to a lesser extent Extenswe use o f these trypanoc~des has resulted m the a p p e a r a n c e of t r y p a n o s o m e stratus resistant *Correspondence andpresent address Swiss Tropical Institute, Soclnstr 57, CH-4002 Basel, Switzerland

0001-706X/91/$03 50 © 1991 Elsevier Science Pubhshers B V

234 to these drugs (Leach and Roberts, 1981, Pmder and Authle, 1984, Rottcher and Schllllnger, 1985, Mbwambo et al, 1988) Some strains of T evanst isolated in China have been found to be resistant to Berenll (Zhang et al, 1990) The arsenical melarsoprol (Mel B) is still the most effective drug for treating the late stages of human trypanosomlasls However, although melamlnyl arsenicals have also been used against experimental surra disease caused by T b evans1 in ponies (Gill and Sen, 1971) and in camels (Schllllnger and Rottcher, 1986), it has never been of great importance in veterinary medicine, since the main animal pathogens ofnagana, T congolense and T vzvax were refractory to arsenical treatment (Wllhamson, 1970) Recently a new arsenical, Cymelarsan (Mel Cy) has been used to treat camels artificially infected with T evansl (Tager-Kagan et al, 1989) In the present paper, we report on the sucqessful treatment of buffaloes, naturally infected with T evansl, with Cymelarsan

Materials and methods Area o f Investigation

This work was carried out in two areas endemic for surra disease One was on the outskirts of Nannlng city, Guangxl, from March 1987 to March 1990 The other one was in the Gao Yao county, Guangdong province from April 1988 to April 1989 Buffaloes

Twenty-nine female and nineteen male buffaloes between 5 and 12 years old were used m this investigation They showed the following clinical signs necrosis at the edges of the ears, lachrymatlon, a white-grey exudate in their eyes and swollen legs These buffaloes were naturally infected with T evanst as demonstrated by blood smear examination, and by intrapentoneal inoculation of 2 0 ml of blood from each buffalo into two mice (1 ml/mouse) Tall blood of the mice was subsequently examreed by wet film every two days for at least one month after inoculation Drugs

Cymelarsan (Mel Cy) was kindly supphed by the late Dr E Frledhom of The Rockefeller Umverslty, New York, 1986 Dlmmazene aceturate (Berenll R) was from Hoechst AG, F R G Drugs were dissolved m sterile water immediately before use and injected intramuscularly Process o f treatment in the field

In Nannlng oty, 16 buffaloes were divided into four groups of four The ammals in three groups were given doses of 0 5, 1 0 and l 5 mg/kg Mel Cy The fourth group was treated with 3 5 mg/kg Bereml as control In Gao Yao county, 32 buffaloes were dwlded into eight groups of four The doses administered were 0 25, 0 5, 0 75, l 0, 1 25, l 5 and 3 0 mg/kg of Mel Cy The last group of four animals was treated with 3 5 mg/kg Berenll as control

235 In N a n n m g ctty, buffaloes were c h e c k e d for the results o f t r e a t m e n t by r e m o v i n g a s a m p l e o f 4 ml o f b l o o d f r o m each one a n d u s m g it to i n o c u l a t e f o u r mice (1 m l / m o u s e ) 41 d a y s , 3 m o n t h s , 6 m o n t h s a n d one, t w o a n d three years after t r e a t m e n t N o t r y p a n o s o m e s were f o u n d m the b l o o d o f a n y o f the mice w t t h m the o b s e r v a t m n p e r i o d o f 30 d a y s In G a o Y a o c o u n t y , tests were c a r r i e d o u t 1 m o n t h , 2, 8 a n d 12 m o n t h s after t r e a t m e n t

Results In the g r o u p t r e a t e d with 0 25 m g / k g M e l Cy, relapse o c c u r r e d in two buffaloes 2 m o n t h s after t r e a t m e n t . R e l a p s e was also f o u n d m two o f etght buffaloes t r e a t e d wtth Berentl 2 m o n t h s after t r e a t m e n t All the o t h e r buffaloes s t a y e d negative unttl 12 m o n t h s after d r u g a d m i n i s t r a t i o n T h e results o f the t r e a t m e n t are s h o w n m Table 1 A t the d o s e o f 1 5 m g / k g M e l Cy, a s c l e r o m a a b o u t 2 to 3 5 cm m & a m e t e r was f o u n d at the p o m t o f InJection in three o u t o f eight a n i m a l s T h e s c l e r o m a d i s a p p e a r e d s p o n t a n e o u s l y after one m o n t h A t the dose o f 3 m g / k g , M e l Cy m d u c e d o b v i o u s necrosis o f the tissue at the site o f inJection m all a m m a l s o f the g r o u p But the tissue r e c o v e r e d after a b o u t two months

Discussion Buffaloes n a t u r a l l y mfected wtth T e v a n s t were t r e a t e d in two p r o v i n c e s o f S o u t h e r n C h i n a with a new m e l a m m y l - s u b s t l t u t e d p h e n y l a r s o n a t e , C y m e l a r s a n (Mel Cy) T h e TABLE 1 The treatment of buffaloes naturally infected with T evanst with Cymelarsan (Mel Cy) Study areas

Nannmg

Gao Yao

Number of treated ammals

Dosage (mg/kg)*

4 4 4 4

05 10 15

4

0 25

4 4 4 4 4 4 4

05 0 75 10 1 25 15 30

*All ammals treated with a single dose

Mel Cy

Bereml

35

35

Results No of ammals/ cured or relapse/ days (d) or year (y) 4/cured/3 4/cured/3 4/cured/3 4/cured/3

ys ys ys ys

2/relapse/60 ds 2/cured/1 y 4/cured/l y 4/cured/l y 4/cured/1 y 4/cured/l y 4/cured/l y 4/cured/l y 2/relapse/60 ds 2/cured/l y

236

results showed that all antmals treated with a single dose of 0 5 mg/kg to 3 0 mg/kg were cured and no relapses could be observed wtthm one to three years These results are m accordance with the results of Tager-Kagan et al (1989) who showed that a single dose of 0.625 or 1 25 mg/kg Mel Cy was fully effective and was well tolerated by camels artificially infected with T b evanst At a dose of 0 25 mg/kg, relapse occurred m two out of four treated buffalo within two months after treatment, indicating that the lowest effective dosage to treat T evansl m buffalo might be between 0 25 and 0 5 mg/kg Zweygarth and Kammsky (1990) reported that a single i p m j e c t t o n of 0 4 mg/kg Mei Cy cured mice infected with a qumapyramme and suramm-reslstant stock (CP 893) of T evanst Their results as well as the results of the present study, indicate that Mel Cy ~s a very acttve trypanocldal drug, at least against T evanst Tager-Kagan et ai (1989) reported that at a dose of 3 75 mg/kg Mel Cy, the drug reduced a s~gntficant necrosis of the t~ssue at the point of inoculation whether the mjecUon was subcutaneous or intramuscular Necros~s at the s~te of injection was also found m our study m the buffaloes treated wxth 3 mg/kg Mel Cy In order to avoid this problem, dosages of 1 to 2 mg/kg are recommended

Acknowledgments The authors are grateful to the late Professor E Frledhetm of The Rockefeller Umverslty, New York, U S A for the supply of Cymelarsan, Hoechst AG, F.R G for the supply of Dlmmazene aceturate (Berenll R) We also wish to express our apprectatton to Dr R Brun for comments on the manuscript and Mrs J Jenkins for reading the manuscript

References G111, B S and Sen, D K (1971) Studies on surra V1 Therapeutic activity of Mel B, dxmmazene and 'Te 85' m the equine infection (Trypanosoma evans 0 Indian J Atom Scl 41,743-746 Leach, T M and Roberts, C J (1981) Present status of chemotherapy and chemoprophylaxls of animal trypanosomlasls in the eastern hemisphere Pharmacol Therap 13, 91-147 Luckms, A G (1988) Trypanosoma evanst m Asia Parasltol Today 4, 137-142 Nbwambo, H A , Mella, P N P and Lekakl, K A (1988) Berend (dlmmazene aceturate)-reslstant Trvpanosoma congolense m cattle under natural tsetse challenge in Klbaha, Tanzama Acta Trop, 45, 239-244 Peng, J-S (1987) Trypanosomlasls of domestic ammals Jlangxl Science and Technology Press, (In Chmese) Pmder, M and Authle, E (1984) The appearance of lsometamldmm remstant Trvpanosoma congolense m West Africa Acta Trop 41,247-252 Rottcher, D and Schllhnger, D (1985) Multiple drug resistance m Trvpanosoma vtva,c m the Tana River District of Kenya Vet Rec 177, 557-558 Schllhnger, D and Rottcher, D (1986) Treatment of camels for Trvpanosoma brucet evanst refection (Surra) Wld Anlm Rev 60, 26-32 Tager-Kagan, P , Itard, J and Clair, M (1989) Essal de l'efficaclte du CymelarsanND sur Trypanosoma evansz chez le dromadmre Rev Elev Med Vet Pays Trop 42, 55-61 Wflhamson, J (1970) Rewew of chemotherapeutic and chemoprophylatlc agents In H W Mulhgan (ed), The African Trypanosommsxs, Allen & Unwm Ltd, London, pp 125-221 Zhang, Z Q , Giroud, C and Baltz, T (1990) Drug sensmvlty m vitro and in wvo In Abstr VII Int Congr Parasltol Pans, August 20-24, p 1124 Zweygarth, E and Kammsky, R (1990) Evaluation of an arsenical compound (RM 110, Mel Cy, Cymelarsan) against susceptible and drug-resistant Trypanosoma brucet brucet and T b evanst Trop Med Parasltol 41, 208-212