Development of a technique for standing hand-assisted laparoscopic splenectomy in five horses.

OBJECTIVES: To develop an experimental standing hand-assisted laparoscopic splenectomy (HALS) technique, report the associated peri-operative complications and document the short-term surgical outcomes. METHODS AND RESULTS: Five healthy 300-470 kg horses that underwent standing HALS. Spleens of different weights (2.25-7.0 kg) were removed using this technique. The main complication during surgery was difficulty sectioning the gastrosplenic ligament. The postoperative complications included adhesions of the colon to the nephrosplenic ligament stump and incisional discharge in two horses. CONCLUSIONS: Standing HALS is a feasible experimental procedure for medium-sized horses, which avoids rib excision and general anaesthesia, but requires further development.

Efficacy of enrofloxacin against severe experimental Anaplasma marginale infections in splenectomized calves.

Four Anaplasma marginale-infected splenectomized calves with greater than 25% parasitized erythrocytes received enrofloxacin at 12.5 mg/kg SC twice, 48 hours apart. Two infected splenectomized calves were designated as untreated controls. A precipitous decline in percent parasitized erythrocytes from 39.13% to less than 1% was observed over 12 days following treatment. However, a self-limiting recrudescence of A. marginale parasites was observed within 30 days after treatment. Untreated control calves became moribund and were euthanized. These data indicate that the regimen of enrofloxacin tested herein ameliorates, but does not eliminate, A. marginale infections in splenectomized calves.

In-vivo therapeutic efficacy trial with artemisinin derivative, buparvaquone and imidocarb dipropionate against Babesia equi infection in donkeys.

The therapeutic efficacy of imidocarb, artesunate, arteether, buparvaquone and arteether+buparvaquone combination was evaluated against Babesia equi of Indian origin in splenectomised donkeys with experimentally induced acute infection. Efficacies of these drugs were tested by administering each drug or drug combination to groups of donkeys (having three donkeys each group). One group of donkey was kept as untreated control for comparing the results. Parasitaemia, haematology (WBC, RBC, PCV, granulocytes and haemoglobin), biochemical parameters (SAST, SALT, alkaline phosphatase, albumin/globulin ratio) were monitored at regular intervals. Individually, arteether and buparvaquone were found to have no parasite clearing efficacy and the treated animals died within 5-6 days after showing high parasitaemia and clinical symptoms of the disease. However, artesunate treated animals were able to restrict the parasite multiplication but only during the treatment period. Animals treated with imidocarb and arteether+buparvaquone combination were able to clear the parasite from the blood circulation after 2-5 days post-treatment (PT). After 55-58 days PT, recrudescence of B. equi parasite was observed in both these groups and a mean survival period of 66 days and 69 days, respectively, was recorded in these groups. Results of haemato-biochemical parameters had shown that imidocarb had deleterious effect on the liver function while on the other hand arteether+buparvaquone combination was found to be safe. This limited study indicates that arteether+buparvaquone combination could be a better choice than imidocarb for treating B. equi infection, but further trials are required in detail.

Preliminary development of a live drug-controlled vaccine against bovine babesiosis using the Mongolian gerbil, Meriones unguiculatus.

This study investigated the practicality and potential of the gerbil, Meriones unguiculatus, as a source of live Babesia divergens vaccine and also as a model for the use of the vaccine in cattle. A series of experiments with gerbils concerning vaccine infectivity, immunogenicity and safety were carried out. It was concluded that the use of RPMI medium/40% foetal calf serum as a diluent improved vaccine infectivity, but that the parasitaemia of the blood obtained from donor gerbils had little or no effect. The immunostimulants levamisole and killed Corynebacterium parvum improved vaccine immunogenicity and it was also shown that the subcutaneous route of infection resulted in the greatest host response. Control of vaccine virulence with drugs was only possible when drugs with prophylactic properties, such as imidocarb and long-acting oxytetracycline, were used. More studies are required on all these topics, particularly with regard to their applicability to cattle, and also concerning the possible attenuation of the parasite by manipulation in the gerbil host.

Bovine anaplasmosis: in utero transmission and the immunologic significance of ingested colostral antibodies.

Neonate progeny from 3 Anaplasma-free (clean) and 5 Anaplasma-carrier cows were splenectomized and each was challenge exposed with 5 ml of carrier blood. Prepatent times were between 18 and 25 days in calves born of clean cows and between 21 and 36 days in progeny from carrier dams. The lowest packed cell volume values in the clean group occurred at 25 to 39 days after the challenge inoculation and at 29 to 47 days in the carrier group. Highest parasitemias in the clean-calves ranged between 13% and 51% in 25 to 35 days and between 35% to 64% in 38 to 43 days in the carrier calves. Seven splenectomized calves were inoculated with 60 ml of whole blood from progeny of known Anaplasma-free or Anaplasma-carrier cows. After 183 days, all but 1 calf remained free of anaplasmosis. A 1% parasitemia was first observed in that calf 12 days after inoculation with blood from a calf which showed signs of acute anaplasmosis at birth. The infected neonate's dam had recovered from acute anaplasmosis infection during the middle of the second trimester of the gestation. Although not statistically significant, colostral antibodies and/or other maternal factors did not seem to completely protect progeny, but lengthened the prepatent period and delayed anemia and the climax of parasitemia. Further, it was determined that it was possible for an animal affected with acute anaplasmosis before the 190th day of the gestation to transmit anaplasmosis in utero.