Epidemiological Investigation of Mechanically Transmitted Trypanosomosis (Trypanosoma Vivax) of Domestic Animals in three Districts Bordering Lake Tana ,Ethiopia.
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Date
2004-06
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Addis Ababa University Faculty Of Veterinary Medicine
Abstract
An epidemiological invc~[igatjon o f mechanic ali) transmitted trypanosomosis \\as unde rtaken
at the three districts (l3ahir Dar Zuria. Delllbia and Foge ra) bordering tal..e Tana that arc
located in Amharct :.Jilliona! Regional Stall'. I-.thiapia. The SlUd} \\ a'i conductcu \\ llh the
objecli\es o f determining the prc\alencc of [r~ranosomosis in calth:. ,mall ruminants and
equines. idelllif)ing biting Oil'S and irl\cstigating the presence of drug resistance 10
Isomcthamidiulll chloride and Diminazinc .:lcc!Uratc in the stu dy are as.
rhe mcthodolog) follo\H..'d \\as tha t a total or 1509 cank. 798 small ruminan ts and 749
equines \\ere considered for the prevalence 'IUJ) u<,ing parasitolo£icat method .. (buf)~ -coal
method) and the PC\ ofc<!ch animal \\a.!> Il1casllr~d using hematocrit h:chniqllc", t\ 101a1 of86
Iraps (66 ~Gl and ~() \ ·Ionoconica l) \\crt.: (kplll) cd for Ihe purpo"l' o f 11) .... ur\t.:~, ;\1 Ihe
Fogera districi -IS canle (in Ihe late rain) "cason) and 19 callic (in Ihe earl~ dr) season)
positi\c lor 7hpw/(J\olIw I'/I'CH ancr Ireatmcnl wilh Iso lll clharniJiwl1 chloride and
Dil11inalinc aCl!lUralt.' respecliH:I) \\ere folkl\\~'d for -; Jllonlhs and 24 da~ .... , rl!<;pec ti\l'l)
rhe r('~lIll'i indi caled Ihal Ihl' o \eral1 pre\ akn..::e o f tr~ panoSom O:-.l .... 11l callie "as 6.1 ° °
(92/1509). Pn.!\ akncc "as significanlly (I ·3.~. ]><0.0 0 I.) higher during th,,- late rain) season
9.6°'0 (57 '591) lliJn Ihe e:lrl~ dr) sea .... on I.11 U n(22609) .\1 roger<! Ji"trir.:! \,here Illl' t\\O
scasons \,erc compared. Prevalence at the di.,tflct k .. c1 has sign ifican(1) \ aril.!J (p<O.O I) fr0m
9.6% (57 /5 92) al Fogera dislrict 10 4 .5~0(6 1:13) ilt Rahir Dar and 4th .. (7, 175) al Dl!1l1bia .
Prevalence at a pca'iant association k\cl ha!> ,>ignilicanll~ (p<O,O I) \arit.:d rrom 0% (0/5 4)
(Scbatamit. Bahir Dar) to 15.5°0 (37,239) ("ihin.l_ Fogcra). t\mong small ruminants ('nl) one-
:.hecp 0.8~o (I I :!~) and one gO.ll 0.15% (I (76) \\cre founJ posit!\t.: for 7i"1/1II110\o1I1lI -'>pt.':cie-'>
and none of thl' l'quin~s \\ ere positive. A1Ithl' tr~ panosomc!. cncountcreJ in cank belong to iI
single ::.pt.:ck::. Ill' I \ 'IHLr IlLmcH~r thl! li'l//{//WI(III/U ~pco.:ks in 'ihet.:p ,H1d go.lI ... th ough il
"t:emed T l"/I"/Lt fr om the 1ll0lClllClib of bun~\ -cmU ~JllC3r. il lIas not po,,,ibh.· to gel \\ itl! in
the Ihin ... rnear prep.Hallon madc from Ihe bun~·co'lI \\hich ma~ Iw dUl' to Ihl.! Icr) 101\
number of para::.ill'" in tht.: blood (single par'l ... itl''' per preparation for eat.:h ... pecic ... al tht.': buH)
coal). The PCV for cach species of animal \1:lS \\i lh in the normal range 3\ailabk in
lilernll1re HI(: PC\' or Trim.\' inliXIt.:d c;U1k ( PCV~~1.6. 95°0('1 1().9·~2.3) 11<1"
,\
s ignific:mt l~ (VO.OO I) 100~ e r th an the m:ga t i\C'~ ( pe V '.1504 . 95~'QC I <~ 5. 2-2 5.5 ) and PCV
va lue~ \\'en..: al so signifi cantly and pos it ;\ e l~ 3ssoc ia ted \\ II h bod) co ndi tio n sco re (p<O.OO I ).
and pre gnane) (p<O.O I), and nega tiv ely assoc iated with lac tati o n (p<O .05 ) and pa rity (p <O.O I)
in ~a ttl e There was also a signifi ca nt \ aria tio l1 in pev among the th ree di stricts (p<O.O I) a nd
bet\\ ('c n Ihe 1\\0 <,e350 0S (p":O .OI) in ctl n le.
A to w l o f 71.273 t1 il;!s \~cre caught of \\hi ch 49.353 (69 .1(10) belo ng to SIOIIIOXY.\.
15.875(22.3%) to non- bi ting .\bl\c/{I(f£'. 4.7 15{ 6.6°'0) 10 horse flies and 1.330(1.9%) to
(·hrysop.\ and Ihcr~ \\ as no tse tse fl~ rhe o \crall appa rent densil~ \\ as 216.3 fl ies,lrapday
rhe \lGL trap had a significant ]) (i'<(J.O) hi gh ca tch of ho rse flies than till' ,\lonocorw.:al
\\hen.' as Ihe i\ lonoconical tra p had <l ~ignil ica lll l~ high cat..:h ofS/oll/ox r \ (p<O.OOOI) o\ c r the
'\IGt. trap. lIo\\e\l.::r. the re \~ as no sig nrtican t dim'rence- in catchments bc !\\t'cn the ( \\0 traps
for non -bi ting ,\II1I<:idul! (;"\ U\l ) ami Chry,\o/JS species. SeJ.)I.mal cLlmpa riso n al Fogera dis lrl ct
has re\ calcd Ihat Ihere \\as a slati .. li.:all) "ignificam \ ari nlj on (p<O.OO I )) o f high 11)
calch rn('nl~ in Ihe la te r;li n ~ seaso n than the- carl) d r) ~('a<,on fo r \!3ch t) pc o f lraps aloo r.: and
loge lhcr I,)T SI/JIII().1:\I. hon,c Ilk" ,\Ild ('hrntlf'1 ~peclc" IJU\\ r.:\e-f. then: II i!" rill 'iigniti.:arn
"1'..l.)Onal larialion for the non-biting \ /imidut!. f l) ,p~'cic'i identified include !f\/O/II.I
lI}!.rt'I/Il. ('l!rYlul'l \/I"l'/Jlohalw, S/o/llon I taft ilnJm, S/OlllfH"\'1 /U~/'t/. S_ p lllla. 51 I'lIl1ida S
\0/(111'1/\, \. l(1i('III(I/(I .m d 'ltppoho,\clI ntrll'ga({/ A s.ingle ... pr.:cirnr.:n nfthe gen u .. T(I/Jm/II\ and
1/('11/(/101'0/(/ \\erc al~o encountered.
Of ca ll Ie ~ubjectt'd 10 both Isorncllumiuiulll chlo ridl.' and Diminuinc ace-lur.Jle dnJg
"en"itl \ l1) trial. none llf Ihe animals \\cn.' POSil1\e lor lrypano<;orna durin g the folkm up
pl.' riod and a t th !! end of the trail 1l11'an PCV has signilicantl~ im proved b) 3.6°'11 for
Isorne lhamidium chloride (1= -8,48. 1'<0.0001) tn:a ted gmup £21.7.95%. C I 11.8-23.61 at
da) zero and 16.3. 95% CI-=15.4-17.3 at da) 90 p<:ISI trl.'alrlH:nt) and 1.6°/(1 fo r Dimin;uine
aLeltlrall' (I -·L9. P < (l.OOI) 1n..'31Cd gnmp (20.1. 95% (I 11).0-11 1. al U;I) h'r,) Jnd 12.7.
CJ5°'(I CI~11.6-13,7 at da~ 24 pos t treatment) rc~pC'cti \'ct)
In gcneral. the pre'ot:IH ... ltId~ has indic:lh.:d that Ir~raJHh'lmI1'oi ... Juc to r \'it'(L\' i ... rdatiH.:I)
importan t in canle. and sma ll ru minanh \\ou ld ge l thc infection. Inlec li on \\ ilh I \'Inn ha ...
negali\(,!I) :lfTcclt:d the ]lCV of .:::tl1lc. Variou:-; biting !1u!~ ,11' \ e-tl'rin;jr~-rnl'di.:at imp"rI;lI1U:
arl.' prc~t:nt and het ... t: Ilie' lIerc nnt ell\.:\HlIlt ered dunng the 'o tud~ periuu. -, his indil,;;l1c .. IIl<lt ,
I'IH!\' infection in the ... tud~ area i) trar1'>ll1iw.: d lllechanil';!ll~ mediated b~ bi til1g tl ie-,>_ r l'il'lL\'
inli:.::lioll in .::auic of thc <,tlld~ di,tm:t<, i ... "Clh;t;\C (0 "·,lh hlllllcthamidiulll .::hll)ridl.' (,II 1
XI
mglkg BW dosc ratc) and Diminazine aceturate {3.5 mglkg BW) as a prophylac t ic and normal
curative doscs respective ly. Therefore, a particular attention towards T. v;vax infection in
catt le is essential to contro l the impact of the disease on productivity, Development of control
options that could minim ize bi ting nies especially in seasons of high vec to r pop ul ation is
another task. Treatment of T. vil'at positive cattle with Diminazine acetu ra te would he
effC(;tive and economical till problems of drug resistance might arise due to Diminazine
acelurate. Finall y, further studies on biting flies (species behaviors, breeding habitat, host
preference, control alternatives, relative importance with regard to T. viva'C transmissio n and
other relevant aspects) are recommended.
Description
Keywords
Trypanosoma viwL"'(' biting nics, isomethamidium, diminazinc, season, cattle, small ruminants, equines and districts bordering lake Tana