Prevention of renal infection and urinary shedding in dogs by a Leptospira vaccination.

Prevention of urinary shedding of Leptospira interrogans spp. by chronically infected dogs remains a key objective of the vaccination in dogs against leptospirosis which is a zoonotic disease. An inactivated bivalent vaccine composed of Leptospira interrogans serovars icterohaemorrhagiae [L. icterohaemorrhagiae] and canicola [L. canicola] bacterins was tested for its ability to protect puppies against a challenge exposure with L. icterohaemorrhagiae. The vaccine was administered twice at a 3-week interval to six puppies aged from 8 to 9 weeks. Six other puppies were used as unvaccinated controls. All puppies were challenged 2 weeks after the second vaccine injection by intraperitoneal (IP) administration of L. icterohaemorrhagiae (day 0). Clinical signs, haematological and biochemical changes and evidence of Leptospira in blood, urine and kidney were monitored for 4 weeks after the challenge exposure (days 0-28). Puppies were euthanised on day 28 for post-mortem and histological examinations of liver and kidney. Control group presented clinical pictures of severe or subclinical infection. One dog developed severe clinical signs (hypothermia, depression, anorexia, abdominal pain, dehydration, icterus, weight loss) and died on post-infection day (PID) 7 due to an acute renal failure. Gross and microscopic lesions were in accordance with this clinical pattern. In the five remaining control dogs, the challenge exposure induced mainly a systemic infection including leptospiraemia, leptospiruria and renal carriage. The vaccinated group remained healthy throughout the study period. In conclusion, immunisation with a Leptospira vaccine was shown to protect dogs against symptomatology and leptospiraemia, urine shedding and renal infection.

Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats.

The clinical efficacy of a recombinant feline interferon, rFeIFN-omega, was evaluated for the treatment of cats presented with clinical signs associated with feline leukemia virus (FeLV) infection and FeLV/feline immunodeficiency virus (FIV) coinfection in the field. In this multicentric, double-blind, placebo-controlled trial, 81 cats meeting the inclusion criteria were randomly placed into 2 groups and treated subcutaneously with rFelFN-omega (1 million [M]U/kg per day) or placebo once daily for 5 consecutive days in 3 series (day 0, 14, 60). The cats were monitored for up to 1 year for clinical signs and mortality. During the initial 4-month period, interferon (IFN)-treated cats (n = 39) had significantly reduced clinical scores compared with placebo (n = 42), with all cats having received concomitant supportive therapies. Compared with the control, the IFN-treated group showed significantly lower rates of mortality: 39% versus 59% (1.7-fold higher risk of death for controls) at the 9-month time point and 47% versus 59% (1.4-fold higher risk of death for controls) at the 12-month time point. The IFN treatment was associated with minor but consistent improvement in abnormal hematologic parameters (red blood cell count, packed cell volume, and white blood cell count), apparently underlying the positive effects of IFN on clinical parameters. These data demonstrate that rFeIFN-omega initially has statistically significant therapeutic effects on clinical signs and later on survival of cats with clinical signs associated with FeLV infection and FeLV/FIV coinfection.

Prevention of sand fly attack by topical application of a permethrin/pyriproxyfen combination on dogs.

Dogs are the primary domestic reservoir of Leishmania infantum, the parasite responsible for most cases of human visceral leishmaniasis. A strategy for the control of leishmaniasis would be to inhibit the sand fly bite. A study was designed to measure the prevention of the sand fly attack by spraying a combination of permethrin and pyriproxyfen on dogs artificially exposed to the vector of leishmaniasis. Eight dogs were individually challenged with 100 female sand flies for 1 hour on Days -7, 0, 7, 14, 21, and 28. Four dogs were randomly assigned to a control group and four dogs were treated with topically applied permethrin/pyriproxyfen on Day 0. After each exposure, sand flies were collected, counted, and scored as fed or unfed. Efficacy of the combination for prevention of feeding was based on the number of unfed sand flies (dead or alive). The combination of permethrin/pyriproxyfen demonstrated a significant (P <.05) repellent effect against Phlebotomus perniciosus bites as soon as it was sprayed on the dogs, and its repellent efficacy lasted at least for 28 days. The combination product provided significant (P <.05) knockdown activity against challenge with sand flies for 21 days in adult dogs and 14 days in puppies. These findings indicate that adult animals in endemic areas should be sprayed with the permethrin/pyriproxyfen product at 3- to 4-week intervals, and young dogs should be sprayed at approximately 2-week intervals, to prevent sand fly attack.