- Email: [email protected]
Effects of Trypanosoma vivax on pregnancy of Yankasa sheep and the results of homidium chloride chemotherapy
ELSEVIER
EFFECTS OF Trvoanosoma ti ON PREGNANCY OF YANKASA SHEEP AND THE RESULTS OF HOMIDIUM CHLORIDE CHEMOTHERAPY E.K.Bawa,‘D. 0gwu,2V.0.Sekoni,1
E.O.Oyedipe,’ K.A.N.Esievo’ and J.E.Kambai’
‘National Animal Production Research Institute, Ahmadu Bello University, PMB 1096 Zaria, Nigeria. 2Facu1ty of Veterinary Medicine, Ahmadu Be110University, Zaria , 3College of Chemical and Leather Technology, Samaru Zaria, Nigera. Recieved for publication: April 13, 1999 Accepted: October 27, 1999 ABSTRACT Three groups of pregnant Yankasa ewes, made up of six ewes in each group were assigned at random to first, second and third trimester of pregnancy studies. The ewes were experimentally infected with 1. k to study the effects of the infection on pregnancy and the results of Novidium” Chemotherapy. Three pregnant uninfected ewes served as controls. Fourteen days post infection, the ewes in each trimester study, were paired by weight and assigned to two groups of three ewes each. One group was treated with Novidiumm’ while the other group remained untreated. Of the three ewes in each group, one ewe was killed humanely at 21 days post infection and another at the end of the trimester period. In the first trimester, a ewe with partial fetal resorption was observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the second trimester, abortion and almost complete fetal resorption were observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the third trimester, abortions were observed among the untreated ewes. Abortion of a live fetus and a case of dystocia were observed among the treated ewes. Ewes in the second and third trimesters of pregnancy were more susceptible to the infection, with ewes in the third trimester being most susceptible, as measured by the number of abortions and death of ewes. Fetuses from the untreated ewes in the three trimesters of pregnancy were lower in body weights, than the fetuses from the treated ewes. The uninfected control ewes carried the pregnancies tlo term. NovidiumW1 chemotherapy at 14 days post infection was not beneficial in ameliorating the pathogenicity of T. vivax infection on pregnancy in Yankasa ewes. T. vivax infection of only 14 days was enough to cause irreversible pathology in Yankasa fetuses evidenced by death of fetuses in-utero, dystocia and abortions irrespective of Novidiumlnl chemotherapy. 0 2000 by Elsev~et Science Inc. Key words: Ttypanosomiasis, Yankasa, chemotherapy, autolyzed fetuses, abortions. INTRODUCTION Despite several decades of research, trypanosomiasis is still a major constraint to animal reproduction and productivity in most African countries[ 161. Trypanosomiasis causes variable degrees Theriogenology 54: 1033-l 040,200O 0 2000 Elsevier Sctence Inc.
0093-691 WOO/$-see front matter PII: SOO93-691X(00)00411-8
1034
Theriogenology
of testicular degeneration with total disappearance of spermatozoa in severe cases, increased reaction time and sperm morphological abnormalities[4,17], anestrus, short and irregular estrus cycles[ 1,101 and abortions [6,12]. Cattle infected with T. vivax and 1. congolense have been reported to show abortion during various stages of pregnancy, birth of weak calves, low birth weights and neonatal calf mortalities[3,13,14]. Abortions have also been reported in T. vivax infected Yankasa and trypanotolerant West Atiican Dwarfsheep[6,15 1, while stillbirths have been reported in 1. congolense infected trypanotolerant cattle[ 81. Chemotherapy and chemoprophylaxis have been employed for decades as some of the measures for control of trypanosomiasis by the livestock industry in Nigeria and Africa in general[9]. Despite these measures, little has been achieved in the control of trypanosomiasis and its effects on animal productivity. Consequently, the objective of this study was to determine the effects of 1. w infection on the three trimesters of pregnancy of Yankasa ewes and the results of Novidium(R) [Homidium Chloride] chemotherapy MATERIALS AND METHODS Animals Twenty one uniparous pregnant Yankasa ewes with mean body weights of 32.552.1 kg were selected from 35 ewes, that had earlier been synchronized by placing for 13 days intravaginal progestagen sponges [Veramix@‘, UpJohn Ltd, West Sussex-England], containing 60.0 mg of Medroxyprogesterone. They were then bred by fertile rams, 48 hours after sponge withdrawal. Pregnancy was confirmed in the ewes by radioimmunoassay (FUA) of progesterone (P4) and nonreturn to estrus 21 days aher breeding. The ewes were sprayed against ectoparasites using the acaride Rhodiacide @hone-Poulene Agrochimie, Lyon, Germany], dewormed against helminths using Flukazole[Channelle Loughrea, Galway, Ireland] and treated twice against common hemoparasites in the environment using long acting Terramycin [Pfizer, Ikeja Lagos Nigeria], at 20.0 mg/kg body weight. They were also checked for trypanosomes using the hematocrit-centrifuge technique, huffy coat method (18). Thereafter, ewes were grouped according to body weight and randomly assigned into three groups of six ewes each, for studies of the first, second and third trimester during O-50, 5 1- 10 1 and 102-152 days of pregnancy, respectively. Stabilates of T. vivax (Stabilate 150) obtained from the Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, Ahmadu Belle University, Zaria were used to infect donor goats, used for the transmission of the infection in the experimental ewes at each trimester of pregnancy. The ewes received 2.0 mL of blood from a donor goat by jugular venepuncture at 23,52 and 102 days of pregnancy, for ewes in the fist, second and third trimester respectively. The control group was not infected. The blood contained approximately 2 x 10 6 trypanosomes. Following infection, the ewes were monitored daily for parasitemia by the hematocrit centrifuge technique [ 181. The degree of parasitemia was classified as follows [l]+, occasional trypanosomes seen; [2]++, 1-2 trypanosomes seen; [3]*, 3-20 trypanosomes seen; [4]++++, greater than 20 trypanosomes seen per buf@ coat
Theriogenology
1035
area. Rectal temperatures were taken in the morning, using a centigrade clinical thermometer. Packed cell volume [PCV] were determined using Gelman Hawskley microhematocrit reader [Gelman Hawskley Ltd. England] and recorded as percent[%]. The body weights of the ewes were measured weekly and recorded in kilograms. Fetuses were weighed and recorded in grams, the weights of the fetuses were also expressed as percentages [%I of their dam’s weight [percentage fetal weight] The infection was described in the ewes as mild when there is no obvious signs of anemia shown by pale mucus membranes, no emaciation and abortions. Severe when there is obvious signs of anemia, severe decrease in PCV values and body weights, emaciation and death of ewes. Very severe when ewes aborted before death or died without aborting few days after the development of parasitemia and pyrexia. Fourteen days post infection, the ewes in each trimester were paired by weight. The ewe in a pair group with the most severe signs of anemia and decrease in packed cell volume [PCV] values and or severe clinical signs was treated with NovidiumtR1. Novidiufl’ is a brand of Homidium Chloride manufactured by May and Baker Ltd. Dagenham England. It has great ttypanocidal action against T. vivax The therapeutic dosage used was 1.O mg/kg. body weight. Three ewes were treated in each trimester and three remained untreated. Relapsed infections were treated again. Following treatment, of the three ewes in each group, one untreated and one treated ewes were killed humanely at 21 days post infection and at the end of the trimester. Ewes that died from the infection or were killed, were examined at post mortem. A pair of treated and untreated ewes from each trimester of pregnancy were allowed to carry the pregnancies as long as possible. RESULTS The results of the clinical manifestation of the infection are summarized in Tables 1 and 2. The infected ewes in all trimester groups became parasitemic within 3 to 4 days post infection. Following Novidiumsu treatment, trypanosomes were cleared Tom peripheral blood of the ewes within four days. Clinical signs and pyrexia subsided within six days after clearance of trypanosomes. The PCV values and body weights of the treated ewes in the first and second trimester increased from values seen on the day of treatment, but declined in the treated ewes in the third trimester[Table 21. Fetal Weights In the tirst trimester group, the infection was mild in the untreated ewes, with low loss in body weight [-8.31 %] and decrease in PCV values to 15.0 %[Table 21. Consequently only one fetus from the untreated ewes was lower in body weight than the fetuses from the treated ewes[Table 31. In the second trimester group, the infection was severe in the untreated ewes, with severe loss in body weight [-23.0 %] and decrease in PCV values to 11 .O % [Table 21. All the fetuses from the untreated ewes were lower in body weights and percentage fetal weights than the fetuses from the treated ewes [Table 31. In the third trimester the infection was very severe in the untreated ewes, with severe loss in body weights [-35.5 %] and severe decline in PCV values to 10.0 % [Table 21.
1036
Theriogenology
Table 1. Summary of clinical signs in Yankasa ewes infected with T. vivax in the first, second and third trimesters of pregnancy and not treated with NovidiumtR1 Trimester of pregnancy when inf&ed[days] First(Oto 50) II=6
Second(5lto n=6
101)
Not infected Third(102to152) n=6
[Controls] n=3
Clinical signs Severity of infection a Mild Death of dam 1 Abortion 0 Fetal resorption 1 Dystocia 0 Parturition 0 Parasitemia 4d post infection b Range 0 to 4 Mean 3.4+ 3.7 Rectal temperature(‘C) Range 36.8 to 41.5 Mean 39.6+ 1.2 Packed cell volume(PCV) Range 29.0 to 15.0 Mean 21.32 3.6 Highest percent change in body weight. -8.3 1
Severe 1
1 0 0
Very Severe 4 3 0 0 0
None 0 0 0 0 0
0 to 4 2.92 1.1
0 to 4 2.32 1.2
0 0
38.1 to 40.2 38 8+ 0.6
38.3 to 40.9 39.2+ 0.7
38.2 to 39.2 38.75 0.3
30.0 to 11.0 22.22 4.3
31.6 to 10.0 19.9+ 6.8
26.0 to 36.0 29.e 3.0
-23 .O
-35.5
+6.8
a Severity of infection, mild= no signs of anemia, emaciation, abortion; B = signs of anemia, severe decrease in PCV, emaciation, abortion, death; verv severe = abortion and death b Parasitaemia grade J. = occasional, 2 = 1 to 2,s = 3 to 20, 4= more than 20 observed trypanosomes. Three out of the six infected ewes aborted before death or died without aborting, between 10 to 12 days post infection and before treatment. Two out of the three remaining ewes that did not abort were treated and one was left untreated. All were allowed to carry the pregnancies to term if possible. Gestation and Lambing None of the infected treated and untreated ewes in the first, second and third trimesters of pregnancy carried the pregnancies to term. In the first trimester, the untreated ewe lefl to carry the pregnancy to term, died 41 days post infection, at 64 days of pregnancy. The fetus weighed 3.344gm [0.017%] and was already undergoing resorption of the limbs. The treated ewe had four relapsed episodes, between 14 to 25 days after treatment. Even though the relapsed episodes were treated, the ewe aborted an autolyzed fetus 87 days post infection, at 110 days of pregnancy.
Theriogenology
1037
Table 2. Summary of clinical signs of Yankasa ewes infected with 1. d and third trimester of pregnancy and treated with Novidiuml”‘.
in the first, second
Trimester of pregnancy when infected and treated[days] First(Oto 50) n=6 Clinical signs 0 Death of dam Abortion 1 Fetal resorption 0 Autolysed fetus 1 0 Dystocia Parturition 0 Parasitemia post treatment Range 0 to 3” Mean 1.5k2.1 Rectal temperature(‘C) 37.5 to 40.1 Range Mean 38.95 0.8 Packed cell volume(PCV) Range 15.0 to 27.0b Mean 20.9% 3.6 Highest percent change in bode weight. +6.2b
Second(5lto
101)
n=6
Third( lO2to 152) n=6
Not infected [Controls] n=3
0
1 0 0 1 1” 0
0
0
0
38.2 to 41.3 39.2+ 0.8
38.7 to 40.9 39.2+ 0.7
38.2 to 39.2 38.7+ 0.3
17.0 to 27.0b 21.3+ 2.8
25.0 to 22.0” 22.72+ 2.4
0 to 4” 2.02 2.8
+16.31b
-27.0
26.0 to 36.0 29.0+ 3.0 +6.8
a Cases of relapsed infections bPCV and body weights valuesincreased from the values on the day of treatment. ’ PCV values further declined from the values on the day of treatment d Refers to the case of dystocia In second trimester, the untreated ewe left to carry the pregnancy to term, died 11 days post infection, at 63 days of pregnancy. The fetus recovered from that ewe was almost completely resorbed and very small, weighing 0.531 mg[0.00005%]. The treated ewe had three relapsed episodes between 21 to 43 days after treatment. The relapsed episodes were treated. Despite the repeated treatments, the ewe aborted an autolyzed fetus 54 days post infection, at 106 days of pregnancy. The untreated ewe in the third trimester of pregnancy aborted 32 days post infection, at 134 days of pregnancy. One of the treated ewes aborted 40 days post infection, 142 days of pregnancy. While the other treated ewe had a dystocia 40 days post infection, at 146 days of pregnancy. The control ewes carried pregnancies to term and had normal deliveries between 150 to 152 days of gestation.
Theriogenology Table 3. Weights[gl and percentage[%] weights of fetuses and lambs from T. vivax infected-treated and infected- untreated Yankasa ewes, killed humanely at 21 days post infection and at the end of each trimester.
Trimester of Pregnancy . when infected/treated Days pi.
21
First trimester
Second trimester
Third trimester
Untreated
Untreated
Untreated
Treated
Treated
Control Treated
0.43g
1.49g
71.2g
126.843
950.0#g’0
0.002%
0 007%
0.36%
0.70%
4.8%
-
820.og*‘* 3.9%
-
83O.Og*” 3.8%
28
l.llOg 0.004%
1.114g 0.004%
49
134.78
53o.og
0.61%
2.24%
910.0*32g 4.8% -
93o.o*=g
2ooo.og
4.2%
8.7%
1114.0+40
23oo.og
g 5.8%
9.1%
-
19oo.og 8.6%
Mean %
0.007g
1.3og
102.958
328.428
877.58
1035g
20678
0.004%
0.005%
0.49%
1.55%
4.3%
5.25%
8.8%
Ewes in the treated groups, were treated at 14 days after infection. Percentage fetal weight is weight of fetus expressed as percentage of dams weight. Fiqures in superscripts are days post infection when ewe aborted, died or had a dystocia * aborted fetuses; + dystocia; # ewe died without aborting. Pi = post infection.
Theriogenology
1039
DISCUSSION The infected ewes developed clinical trypanosomiasis similar to that described in earlier reports[l1,14]. Individual variations similar to those reported in cattle were also observed[7]. Deaths and abortions due to the infection were common in the untreated ewes in the second and third trimester, with ewes in the third trimester being most susceptible as measured by the number of abortions and death ofewes. The trimester of pregnancy influenced the severity and outcome of the infection. Similar observations have been reported in cattle[ 131. The low fetal body weights and percentage fetal weights observed in the fetuses of untreated ewes in the first and second trimesters of pregnancy in this study, give credence to reports of low fetal body weights in fetuses from T. vivax infected West African Dwarf sheep [2,15]. The study showed that Novidium@) chemotherapy was partially beneficial in the treated ewes, evidenced by the higher body weights and percentage fetal weights of the fetuses from the treated ewes, than the fetuses from the untreated ewes and also preventing abortions early in the infection, in the treated ewes. It was observed from the study that T. vivax infection of a short duration in pregnant Yankasa ewes was enough to cause irreversible foetal pathology evidenced by fetal resorption, fetal death in-utero, abortions or dystocia. The recurrence of parasitemia after repeated chemotherapy with Novidium@) again demonstrates the increasing resistance of trypanosomes to one of the most widely used trypanocide and this underscores the need for the development of new pharmaceutical. Novidium’R’chemotherapy at 14 days post infection, in pregnant Yankasa ewes ameliorated the pathogenic effects of 1. k infection on fetal weights in pregnant ewes, but did not prevent abortion. Further investigation is therefore recommended to determine the best time for Novidium(R) chemotherapy in infected pregnant Yankasa ewes to achieve complete amelioration of the pathogenic effects of 1. w on pregnancy in Yankasa ewes. REFERENCES 1. Adenowo TK. Effects of Experimental Trvpanosoma vivax infection on the estrus cycle of Yankasa ewes.(MSc. thesis) Ahmadu Bello University; 1989: 156- 165. 2. Akinbamijo 00, Reynolds L, Gort C. Effects of Trypanosoma w infection during pregnancy on feed intake, nitrogen retention and liveweight changes in West African Dwarf ewes. .I Agric Sci 1994; 123: 379-385. 3 Anene BM, Chime AB, Anika SM. The Production performance of imported Friesian Cattle Under heavy Trypanosoma challenge in rain forest zone of Nigeria. Br Vet J 1991; 147: 275282. 4. Anosa VO, Isoun TT. Further observations on testicular pathology in Trypanosoma & infection of sheep and goats. Res Vet Sci 1980; 28: 15 1- 160. 5. Anosa VO, Isoun TT. Pathology of experimental Trypanosoma Gv& infection of sheep and goats. Zentbl Vet Med (B) 1983; 30. 685-700.
1040
Theriogenology
6. Bawa EK, Oyedipe EO, Sannusi A, Eduvie, LO, Ogwu D, Esievo KAN Effects of Trvoanosoma
& infection on pregnancy in Yankasa and West African Dwarf sheep: Comparative clinical observation between Yankasa and WAD sheep, following infection at middle and late stages of pregnancy (A preliminary study).Bulletin NAPRI, Ahmadu Belle University 1990; 87-89. 7. Desowitz RS. Studies on Imnnmity and Host-Parasite Relations.I.The Immunological response of resistant and susceptible breeds of cattle to Trypanosoma challenge. Ann Trop Med Parasitol 1959; 53: 293-313. 8. Djabakou K, Grundler G, Fimmen HO, Adomefa K. Abortions caused by &panosoma coneolense in Ndama and Boule cattle. Trypanotolerance et. Production Animals 1985; 4: S-8. 9. International Livestck Centre for Africa Addis Ababa, Ethiopia. Annual Report 1990: 33-43. 10. Llwelyn CA Luckins AG, Mumo CD, Perrier J. The effects of Trypanosoma congolense infection on the es&us cycle of the goat Br Vet J 1988; 143: 423-43 1. 11. Lossos GJ. Infections caused by pathogenic African trypanosomes. In. Proc, Workshop held at Nairobi, Kenya 20-23 Nov. 1978; Edited by G. Lossos and A, Ghouinard. IDRC Ottawa, Canada. 59-62. 12. Ogwu D. Effects of Trypanosoma d infection on female reproduction in cattle.(PhD. thesis) Ahmadu Bello University; 1983: 89-l 14. 13. Ogwu D, Njoku CO. Effects of pregnancy on clinical manifestation of bovine trypanosomiasis. Vet Parasitol 1987; 24: 25-33. 14. Ogwu D, Njoku CO, Osori DIK. The effects of experimental Trynanosoma y&~ infection on first, second and third trimester pregnancy of heifers. Theriogenology 1986; 25: 283-398. 15. Reynolds L, Ekwuruke JO. Effects of Trvpanosoma w infection on West African Dwarf sheep at two planes of nutrition. Small ruminants Res 1988; 1: 175-188. 16. Sekoni VO. Reproductive disorders caused by Animal Trypanosomiasis,, A Review. Therigenology 1994; 42: 557-570. 17. Sekoni VO, Kumi-Diaka J, Saror D, Njoku CO. The effects of manosoma y&~ and Trypanosoma coneolense infection on reaction time and semen characteristics in Zebu bulls. Br Vet .I. 1988; 144: 388-394. 18. Woo PTK. The hematocrit centrifuge technique for the detection of trypanosomes in blood, Canandian J Zool 1969; 47: 921-923.
EFFECTS OF Trvoanosoma ti ON PREGNANCY OF YANKASA SHEEP AND THE RESULTS OF HOMIDIUM CHLORIDE CHEMOTHERAPY E.K.Bawa,‘D. 0gwu,2V.0.Sekoni,1
E.O.Oyedipe,’ K.A.N.Esievo’ and J.E.Kambai’
‘National Animal Production Research Institute, Ahmadu Bello University, PMB 1096 Zaria, Nigeria. 2Facu1ty of Veterinary Medicine, Ahmadu Be110University, Zaria , 3College of Chemical and Leather Technology, Samaru Zaria, Nigera. Recieved for publication: April 13, 1999 Accepted: October 27, 1999 ABSTRACT Three groups of pregnant Yankasa ewes, made up of six ewes in each group were assigned at random to first, second and third trimester of pregnancy studies. The ewes were experimentally infected with 1. k to study the effects of the infection on pregnancy and the results of Novidium” Chemotherapy. Three pregnant uninfected ewes served as controls. Fourteen days post infection, the ewes in each trimester study, were paired by weight and assigned to two groups of three ewes each. One group was treated with Novidiumm’ while the other group remained untreated. Of the three ewes in each group, one ewe was killed humanely at 21 days post infection and another at the end of the trimester period. In the first trimester, a ewe with partial fetal resorption was observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the second trimester, abortion and almost complete fetal resorption were observed among the untreated ewes. Fetal death in-utero and expulsion of an autolyzed fetus was observed among the treated ewes. In the third trimester, abortions were observed among the untreated ewes. Abortion of a live fetus and a case of dystocia were observed among the treated ewes. Ewes in the second and third trimesters of pregnancy were more susceptible to the infection, with ewes in the third trimester being most susceptible, as measured by the number of abortions and death of ewes. Fetuses from the untreated ewes in the three trimesters of pregnancy were lower in body weights, than the fetuses from the treated ewes. The uninfected control ewes carried the pregnancies tlo term. NovidiumW1 chemotherapy at 14 days post infection was not beneficial in ameliorating the pathogenicity of T. vivax infection on pregnancy in Yankasa ewes. T. vivax infection of only 14 days was enough to cause irreversible pathology in Yankasa fetuses evidenced by death of fetuses in-utero, dystocia and abortions irrespective of Novidiumlnl chemotherapy. 0 2000 by Elsev~et Science Inc. Key words: Ttypanosomiasis, Yankasa, chemotherapy, autolyzed fetuses, abortions. INTRODUCTION Despite several decades of research, trypanosomiasis is still a major constraint to animal reproduction and productivity in most African countries[ 161. Trypanosomiasis causes variable degrees Theriogenology 54: 1033-l 040,200O 0 2000 Elsevier Sctence Inc.
0093-691 WOO/$-see front matter PII: SOO93-691X(00)00411-8
1034
Theriogenology
of testicular degeneration with total disappearance of spermatozoa in severe cases, increased reaction time and sperm morphological abnormalities[4,17], anestrus, short and irregular estrus cycles[ 1,101 and abortions [6,12]. Cattle infected with T. vivax and 1. congolense have been reported to show abortion during various stages of pregnancy, birth of weak calves, low birth weights and neonatal calf mortalities[3,13,14]. Abortions have also been reported in T. vivax infected Yankasa and trypanotolerant West Atiican Dwarfsheep[6,15 1, while stillbirths have been reported in 1. congolense infected trypanotolerant cattle[ 81. Chemotherapy and chemoprophylaxis have been employed for decades as some of the measures for control of trypanosomiasis by the livestock industry in Nigeria and Africa in general[9]. Despite these measures, little has been achieved in the control of trypanosomiasis and its effects on animal productivity. Consequently, the objective of this study was to determine the effects of 1. w infection on the three trimesters of pregnancy of Yankasa ewes and the results of Novidium(R) [Homidium Chloride] chemotherapy MATERIALS AND METHODS Animals Twenty one uniparous pregnant Yankasa ewes with mean body weights of 32.552.1 kg were selected from 35 ewes, that had earlier been synchronized by placing for 13 days intravaginal progestagen sponges [Veramix@‘, UpJohn Ltd, West Sussex-England], containing 60.0 mg of Medroxyprogesterone. They were then bred by fertile rams, 48 hours after sponge withdrawal. Pregnancy was confirmed in the ewes by radioimmunoassay (FUA) of progesterone (P4) and nonreturn to estrus 21 days aher breeding. The ewes were sprayed against ectoparasites using the acaride Rhodiacide @hone-Poulene Agrochimie, Lyon, Germany], dewormed against helminths using Flukazole[Channelle Loughrea, Galway, Ireland] and treated twice against common hemoparasites in the environment using long acting Terramycin [Pfizer, Ikeja Lagos Nigeria], at 20.0 mg/kg body weight. They were also checked for trypanosomes using the hematocrit-centrifuge technique, huffy coat method (18). Thereafter, ewes were grouped according to body weight and randomly assigned into three groups of six ewes each, for studies of the first, second and third trimester during O-50, 5 1- 10 1 and 102-152 days of pregnancy, respectively. Stabilates of T. vivax (Stabilate 150) obtained from the Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, Ahmadu Belle University, Zaria were used to infect donor goats, used for the transmission of the infection in the experimental ewes at each trimester of pregnancy. The ewes received 2.0 mL of blood from a donor goat by jugular venepuncture at 23,52 and 102 days of pregnancy, for ewes in the fist, second and third trimester respectively. The control group was not infected. The blood contained approximately 2 x 10 6 trypanosomes. Following infection, the ewes were monitored daily for parasitemia by the hematocrit centrifuge technique [ 181. The degree of parasitemia was classified as follows [l]+, occasional trypanosomes seen; [2]++, 1-2 trypanosomes seen; [3]*, 3-20 trypanosomes seen; [4]++++, greater than 20 trypanosomes seen per buf@ coat
Theriogenology
1035
area. Rectal temperatures were taken in the morning, using a centigrade clinical thermometer. Packed cell volume [PCV] were determined using Gelman Hawskley microhematocrit reader [Gelman Hawskley Ltd. England] and recorded as percent[%]. The body weights of the ewes were measured weekly and recorded in kilograms. Fetuses were weighed and recorded in grams, the weights of the fetuses were also expressed as percentages [%I of their dam’s weight [percentage fetal weight] The infection was described in the ewes as mild when there is no obvious signs of anemia shown by pale mucus membranes, no emaciation and abortions. Severe when there is obvious signs of anemia, severe decrease in PCV values and body weights, emaciation and death of ewes. Very severe when ewes aborted before death or died without aborting few days after the development of parasitemia and pyrexia. Fourteen days post infection, the ewes in each trimester were paired by weight. The ewe in a pair group with the most severe signs of anemia and decrease in packed cell volume [PCV] values and or severe clinical signs was treated with NovidiumtR1. Novidiufl’ is a brand of Homidium Chloride manufactured by May and Baker Ltd. Dagenham England. It has great ttypanocidal action against T. vivax The therapeutic dosage used was 1.O mg/kg. body weight. Three ewes were treated in each trimester and three remained untreated. Relapsed infections were treated again. Following treatment, of the three ewes in each group, one untreated and one treated ewes were killed humanely at 21 days post infection and at the end of the trimester. Ewes that died from the infection or were killed, were examined at post mortem. A pair of treated and untreated ewes from each trimester of pregnancy were allowed to carry the pregnancies as long as possible. RESULTS The results of the clinical manifestation of the infection are summarized in Tables 1 and 2. The infected ewes in all trimester groups became parasitemic within 3 to 4 days post infection. Following Novidiumsu treatment, trypanosomes were cleared Tom peripheral blood of the ewes within four days. Clinical signs and pyrexia subsided within six days after clearance of trypanosomes. The PCV values and body weights of the treated ewes in the first and second trimester increased from values seen on the day of treatment, but declined in the treated ewes in the third trimester[Table 21. Fetal Weights In the tirst trimester group, the infection was mild in the untreated ewes, with low loss in body weight [-8.31 %] and decrease in PCV values to 15.0 %[Table 21. Consequently only one fetus from the untreated ewes was lower in body weight than the fetuses from the treated ewes[Table 31. In the second trimester group, the infection was severe in the untreated ewes, with severe loss in body weight [-23.0 %] and decrease in PCV values to 11 .O % [Table 21. All the fetuses from the untreated ewes were lower in body weights and percentage fetal weights than the fetuses from the treated ewes [Table 31. In the third trimester the infection was very severe in the untreated ewes, with severe loss in body weights [-35.5 %] and severe decline in PCV values to 10.0 % [Table 21.
1036
Theriogenology
Table 1. Summary of clinical signs in Yankasa ewes infected with T. vivax in the first, second and third trimesters of pregnancy and not treated with NovidiumtR1 Trimester of pregnancy when inf&ed[days] First(Oto 50) II=6
Second(5lto n=6
101)
Not infected Third(102to152) n=6
[Controls] n=3
Clinical signs Severity of infection a Mild Death of dam 1 Abortion 0 Fetal resorption 1 Dystocia 0 Parturition 0 Parasitemia 4d post infection b Range 0 to 4 Mean 3.4+ 3.7 Rectal temperature(‘C) Range 36.8 to 41.5 Mean 39.6+ 1.2 Packed cell volume(PCV) Range 29.0 to 15.0 Mean 21.32 3.6 Highest percent change in body weight. -8.3 1
Severe 1
1 0 0
Very Severe 4 3 0 0 0
None 0 0 0 0 0
0 to 4 2.92 1.1
0 to 4 2.32 1.2
0 0
38.1 to 40.2 38 8+ 0.6
38.3 to 40.9 39.2+ 0.7
38.2 to 39.2 38.75 0.3
30.0 to 11.0 22.22 4.3
31.6 to 10.0 19.9+ 6.8
26.0 to 36.0 29.e 3.0
-23 .O
-35.5
+6.8
a Severity of infection, mild= no signs of anemia, emaciation, abortion; B = signs of anemia, severe decrease in PCV, emaciation, abortion, death; verv severe = abortion and death b Parasitaemia grade J. = occasional, 2 = 1 to 2,s = 3 to 20, 4= more than 20 observed trypanosomes. Three out of the six infected ewes aborted before death or died without aborting, between 10 to 12 days post infection and before treatment. Two out of the three remaining ewes that did not abort were treated and one was left untreated. All were allowed to carry the pregnancies to term if possible. Gestation and Lambing None of the infected treated and untreated ewes in the first, second and third trimesters of pregnancy carried the pregnancies to term. In the first trimester, the untreated ewe lefl to carry the pregnancy to term, died 41 days post infection, at 64 days of pregnancy. The fetus weighed 3.344gm [0.017%] and was already undergoing resorption of the limbs. The treated ewe had four relapsed episodes, between 14 to 25 days after treatment. Even though the relapsed episodes were treated, the ewe aborted an autolyzed fetus 87 days post infection, at 110 days of pregnancy.
Theriogenology
1037
Table 2. Summary of clinical signs of Yankasa ewes infected with 1. d and third trimester of pregnancy and treated with Novidiuml”‘.
in the first, second
Trimester of pregnancy when infected and treated[days] First(Oto 50) n=6 Clinical signs 0 Death of dam Abortion 1 Fetal resorption 0 Autolysed fetus 1 0 Dystocia Parturition 0 Parasitemia post treatment Range 0 to 3” Mean 1.5k2.1 Rectal temperature(‘C) 37.5 to 40.1 Range Mean 38.95 0.8 Packed cell volume(PCV) Range 15.0 to 27.0b Mean 20.9% 3.6 Highest percent change in bode weight. +6.2b
Second(5lto
101)
n=6
Third( lO2to 152) n=6
Not infected [Controls] n=3
0
1 0 0 1 1” 0
0
0
0
38.2 to 41.3 39.2+ 0.8
38.7 to 40.9 39.2+ 0.7
38.2 to 39.2 38.7+ 0.3
17.0 to 27.0b 21.3+ 2.8
25.0 to 22.0” 22.72+ 2.4
0 to 4” 2.02 2.8
+16.31b
-27.0
26.0 to 36.0 29.0+ 3.0 +6.8
a Cases of relapsed infections bPCV and body weights valuesincreased from the values on the day of treatment. ’ PCV values further declined from the values on the day of treatment d Refers to the case of dystocia In second trimester, the untreated ewe left to carry the pregnancy to term, died 11 days post infection, at 63 days of pregnancy. The fetus recovered from that ewe was almost completely resorbed and very small, weighing 0.531 mg[0.00005%]. The treated ewe had three relapsed episodes between 21 to 43 days after treatment. The relapsed episodes were treated. Despite the repeated treatments, the ewe aborted an autolyzed fetus 54 days post infection, at 106 days of pregnancy. The untreated ewe in the third trimester of pregnancy aborted 32 days post infection, at 134 days of pregnancy. One of the treated ewes aborted 40 days post infection, 142 days of pregnancy. While the other treated ewe had a dystocia 40 days post infection, at 146 days of pregnancy. The control ewes carried pregnancies to term and had normal deliveries between 150 to 152 days of gestation.
Theriogenology Table 3. Weights[gl and percentage[%] weights of fetuses and lambs from T. vivax infected-treated and infected- untreated Yankasa ewes, killed humanely at 21 days post infection and at the end of each trimester.
Trimester of Pregnancy . when infected/treated Days pi.
21
First trimester
Second trimester
Third trimester
Untreated
Untreated
Untreated
Treated
Treated
Control Treated
0.43g
1.49g
71.2g
126.843
950.0#g’0
0.002%
0 007%
0.36%
0.70%
4.8%
-
820.og*‘* 3.9%
-
83O.Og*” 3.8%
28
l.llOg 0.004%
1.114g 0.004%
49
134.78
53o.og
0.61%
2.24%
910.0*32g 4.8% -
93o.o*=g
2ooo.og
4.2%
8.7%
1114.0+40
23oo.og
g 5.8%
9.1%
-
19oo.og 8.6%
Mean %
0.007g
1.3og
102.958
328.428
877.58
1035g
20678
0.004%
0.005%
0.49%
1.55%
4.3%
5.25%
8.8%
Ewes in the treated groups, were treated at 14 days after infection. Percentage fetal weight is weight of fetus expressed as percentage of dams weight. Fiqures in superscripts are days post infection when ewe aborted, died or had a dystocia * aborted fetuses; + dystocia; # ewe died without aborting. Pi = post infection.
Theriogenology
1039
DISCUSSION The infected ewes developed clinical trypanosomiasis similar to that described in earlier reports[l1,14]. Individual variations similar to those reported in cattle were also observed[7]. Deaths and abortions due to the infection were common in the untreated ewes in the second and third trimester, with ewes in the third trimester being most susceptible as measured by the number of abortions and death ofewes. The trimester of pregnancy influenced the severity and outcome of the infection. Similar observations have been reported in cattle[ 131. The low fetal body weights and percentage fetal weights observed in the fetuses of untreated ewes in the first and second trimesters of pregnancy in this study, give credence to reports of low fetal body weights in fetuses from T. vivax infected West African Dwarf sheep [2,15]. The study showed that Novidium@) chemotherapy was partially beneficial in the treated ewes, evidenced by the higher body weights and percentage fetal weights of the fetuses from the treated ewes, than the fetuses from the untreated ewes and also preventing abortions early in the infection, in the treated ewes. It was observed from the study that T. vivax infection of a short duration in pregnant Yankasa ewes was enough to cause irreversible foetal pathology evidenced by fetal resorption, fetal death in-utero, abortions or dystocia. The recurrence of parasitemia after repeated chemotherapy with Novidium@) again demonstrates the increasing resistance of trypanosomes to one of the most widely used trypanocide and this underscores the need for the development of new pharmaceutical. Novidium’R’chemotherapy at 14 days post infection, in pregnant Yankasa ewes ameliorated the pathogenic effects of 1. k infection on fetal weights in pregnant ewes, but did not prevent abortion. Further investigation is therefore recommended to determine the best time for Novidium(R) chemotherapy in infected pregnant Yankasa ewes to achieve complete amelioration of the pathogenic effects of 1. w on pregnancy in Yankasa ewes. REFERENCES 1. Adenowo TK. Effects of Experimental Trvpanosoma vivax infection on the estrus cycle of Yankasa ewes.(MSc. thesis) Ahmadu Bello University; 1989: 156- 165. 2. Akinbamijo 00, Reynolds L, Gort C. Effects of Trypanosoma w infection during pregnancy on feed intake, nitrogen retention and liveweight changes in West African Dwarf ewes. .I Agric Sci 1994; 123: 379-385. 3 Anene BM, Chime AB, Anika SM. The Production performance of imported Friesian Cattle Under heavy Trypanosoma challenge in rain forest zone of Nigeria. Br Vet J 1991; 147: 275282. 4. Anosa VO, Isoun TT. Further observations on testicular pathology in Trypanosoma & infection of sheep and goats. Res Vet Sci 1980; 28: 15 1- 160. 5. Anosa VO, Isoun TT. Pathology of experimental Trypanosoma Gv& infection of sheep and goats. Zentbl Vet Med (B) 1983; 30. 685-700.
1040
Theriogenology
6. Bawa EK, Oyedipe EO, Sannusi A, Eduvie, LO, Ogwu D, Esievo KAN Effects of Trvoanosoma
& infection on pregnancy in Yankasa and West African Dwarf sheep: Comparative clinical observation between Yankasa and WAD sheep, following infection at middle and late stages of pregnancy (A preliminary study).Bulletin NAPRI, Ahmadu Belle University 1990; 87-89. 7. Desowitz RS. Studies on Imnnmity and Host-Parasite Relations.I.The Immunological response of resistant and susceptible breeds of cattle to Trypanosoma challenge. Ann Trop Med Parasitol 1959; 53: 293-313. 8. Djabakou K, Grundler G, Fimmen HO, Adomefa K. Abortions caused by &panosoma coneolense in Ndama and Boule cattle. Trypanotolerance et. Production Animals 1985; 4: S-8. 9. International Livestck Centre for Africa Addis Ababa, Ethiopia. Annual Report 1990: 33-43. 10. Llwelyn CA Luckins AG, Mumo CD, Perrier J. The effects of Trypanosoma congolense infection on the es&us cycle of the goat Br Vet J 1988; 143: 423-43 1. 11. Lossos GJ. Infections caused by pathogenic African trypanosomes. In. Proc, Workshop held at Nairobi, Kenya 20-23 Nov. 1978; Edited by G. Lossos and A, Ghouinard. IDRC Ottawa, Canada. 59-62. 12. Ogwu D. Effects of Trypanosoma d infection on female reproduction in cattle.(PhD. thesis) Ahmadu Bello University; 1983: 89-l 14. 13. Ogwu D, Njoku CO. Effects of pregnancy on clinical manifestation of bovine trypanosomiasis. Vet Parasitol 1987; 24: 25-33. 14. Ogwu D, Njoku CO, Osori DIK. The effects of experimental Trynanosoma y&~ infection on first, second and third trimester pregnancy of heifers. Theriogenology 1986; 25: 283-398. 15. Reynolds L, Ekwuruke JO. Effects of Trvpanosoma w infection on West African Dwarf sheep at two planes of nutrition. Small ruminants Res 1988; 1: 175-188. 16. Sekoni VO. Reproductive disorders caused by Animal Trypanosomiasis,, A Review. Therigenology 1994; 42: 557-570. 17. Sekoni VO, Kumi-Diaka J, Saror D, Njoku CO. The effects of manosoma y&~ and Trypanosoma coneolense infection on reaction time and semen characteristics in Zebu bulls. Br Vet .I. 1988; 144: 388-394. 18. Woo PTK. The hematocrit centrifuge technique for the detection of trypanosomes in blood, Canandian J Zool 1969; 47: 921-923.