Examining the Relationship of Clinical and Laboratory Parameters With Infectiousness to Phlebotomus perniciosus and Its Potential Infectivity in Dogs With Overt Clinical Leishmaniasis.

Infected dogs are considered the main domestic animal reservoirs for Leishmania infantum parasite. Infectiousness to competent phlebotomine vectors has been associated with many factors, the main being the severity of the disease exhibited by infected dogs. This study examines the relationship between different clinical parameters and the infectiousness to colonized Phlebotomus perniciosus sand flies having a blood meal on dogs. Data obtained in the present study come from an untreated group of Leishmania sick dogs submitted to xenodiagnosis for the evaluation of a spot on insecticide solution. Seventeen dogs were diagnosed as affected by leishmaniasis through clinical examination, immunofluorescence antibody test (IFAT) serology, and loop-mediated isothermal amplification (LAMP). The disease severity (clinical score) was staged by using a numeric value derived from eight clinical and parasitological parameters. Xenodiagnosis was performed on caged dogs exposed for 1.5 h to sand-fly bites. The following parameters related to sand flies were examined: blood feeding (% of blood engorged females), promastigote detection (% of promastigote-positive sand flies), promastigote burden, and the promastigote stage maturation (potential transmissibility rate). Statistical relationship between the clinical score and entomological parameters was investigated, as well as the possible correlation between each clinical and laboratory parameters and sand fly infection/infectivity. The severity of clinical score may influence the blood feeding by, and the probability of promastigote detection in, sand flies; skin lesions seem to be the main factor that influences the rate of blood feeding. Promastigote burden is related to IFAT titer, skin lesions, and clinical score. All entomological parameters are strongly related among them. This study confirms that both P. perniciosus infection and infectivity are influenced by a dog's clinical condition.

Evaluation of inflammation and immunity in cats with spontaneous parvovirus infection: consequences of recombinant feline interferon-omega administration.

Administration of recombinant feline interferon-omega (rFeIFN) has been proposed for the prophylaxis of canine and feline parvovirosis. In the present study, the influence of the administration of rFeIFN on blood markers of inflammation (alpha-globulins, alpha(1)-acid glycoprotein) and immune system activation (gamma-globulins, IgG, IgM, specific anti-feline parvovirus IgG or IgM) was evaluated in a cattery developing an outbreak of feline panleukopenia due to feline parvovirus (FPV) infection few days after initial administration of rFeIFN. Kittens (n=23) were injected with rFeIFN (1MU/kg subcutaneously, once a day for 3 days) and their blood parameters were compared with those of 17 untreated cats. Cats that survived the outbreak were vaccinated and re-sampled 1 month after the last rFeIFN administration. Time of emergence of clinical signs and survival rate were not significantly different between the two groups. Controls and treated cats surviving the infection had high levels of gamma-globulins, total- and anti-FPV specific IgGs, likely due to passive transfer of maternal immunity. Compared to controls, treated kittens had lower levels of alpha(1)-globulins and higher mean values of gamma-globulins and immunoglobulins. Data from samples collected after vaccination revealed a higher level of gamma-globulins, total- and anti-FPV specific IgGs in treated kittens, compared with controls, suggesting that rFeIFN stimulates antibody production. Based on this results, rFeIFN should be administered to the queen, to increase passive maternal immunity, or to kittens before introduction in a potentially contaminated environment.