Notes on the routine intravenous use of isometamidium in the control of bovine trypanosomiasis on the Kenya coast

Abstract

Various chemotherapeutic regimes were used to control trypanosomiasis in 3,000 Boran cattle on an estate on the Kenya coast. Recently the therapeutic use of isometamidium by the intravenous route was adopted to treat individual trypanosome-infected cattle. This was in order to overcome tissue reactions encountered after intramuscular injection and also to control a "thin cow" syndrome attributed to chronic trypanosomiasis. Toxic side effects were eliminated by careful attention to the intravenous technique which was safely used in calves, pregnant cattle and bulls. Weekly blood sampling and treatments of infected individuals resulted in a reduction of cases from 2,187 to 208 out of 46,495 and 46,329 samples examined in 1985 and 1986 respectively. The standard of management was very high and although this routine successfully controlled bovine trypanosomiasis on this estate its application elsewhere is likely to be limited.

Safety and efficacy of three trypanocides in confirmed field cases of trypanosomiasis in working equines in The Gambia: a prospective, randomised, non-inferiority trial

“…A low therapeutic index and dose-dependent toxicity [67] related to an anticholinesterase effect [68] has been documented in other species, producing similar signs. The adverse reaction is associated with decreased serum cations (calcium, magnesium, sodium and potassium) [69] consistent with third space losses and occasional deaths have been reported in cattle [70]. The small stature of donkeys could render them more vulnerable to over-estimation of body weight.…”

“…Due to a high baseline prevalence of diarrhoea (17/639; 3%) and abortion (60/340; 18% of female equines) in this population, both of which are also reported clinical signs of trypanosomiasis, interpretation of other potential adverse responses to treatment requires caution. There have been no previous associations between the trypanocides used in this study and these clinical signs and their safety in pregnancy has been evaluated in other species with no evidence of increased risk (isometamidium [70], diminazene [73] and melarsomine dihydrochloride [61,74]). Previous studies have raised concerns regarding the use of diminazene in equines [26] especially donkeys where development of central nervous signs had been reported [75].…”

Trypanosomiasis control in Boran cattle in Kenya: A comparison between chemoprophylaxis and a parasite detection and intravenous treatment method using isometamidium chloride

“…Kalu (1983) considered that cryptic trypanosomes which are not reached by plasma levels produced by the depot formation of isometamidium chloride injected intramuscularly are "flushed out" by the high initial plasma level after it is used intravenously. This effect was considered by Dowler et al (1988) to be the main reason for the better weight gain by intravenously treated animals. In this study the curative isometamidium chloride group gained a substantial 38% more weight during 30 weeks than the curative diminazene aceturate group and 31% more than the isometamidium chloride prophylaxis group, the latter gaining only 6% more than the diminazene aceturate group.…”

The animal trypanosomiases and their chemotherapy: a review

“…Multiple intramuscular administrations of isometamidium can cause severe fibrous lesions, hence damaging the carcass and meat quality from livestock. Intravenous administration has been successfully used to abrogate muscular damage, but it has been suggested that this could result in compromised prophylactic activity, due to the lack of a drug depot at the injection site (Dowler et al 1989; Munstermann et al 1992). The duration of prophylactic activity following intramuscular administration in cattle is typically 2–3 months and may be up to 6 months, but can vary greatly, depending on the formulation and dosage used and on the parasite strain, as well as on other factors, including susceptibility of the particular breed and its general health status (Toro et al 1983; Kinabo and Bogan, 1988).…”