Impact of immunological state on eco-physiological variables in one of the southernmost lizards in the world.

The immune state is an essential component of survival as it directly influences physiological performance and health status. Variation in the leukocyte profile, a significantly increase in body temperature, and a detriment of the eco-physiological performance are among the possible consequences of an unhealthy state. In this study we analyse and discuss how field body temperature, preferred body temperature, the speed for sprint and long runs, locomotor stamina, and body condition can be affected by the immunological state (i.e. leukocyte profile) in a wild population of Liolaemus sarmentoi. Juveniles and adult males with a high percentage of eosinophils, basophils, and a low percentage of monocytes preferred higher body temperatures in a thermal gradient, while pregnant females maintained thermal preferences independently of leukocyte profile. Although juveniles with a high percentage of heterophils showed less locomotor stamina, adult males and pregnant females showed no differences in locomotor performance in relation to leukocyte profile. This study represents a starting point in eco-immunology of a wild lizard population of Liolaemus in cold and temperate environments of Patagonia where the southward shift in the geographic ranges of pathogen populations due to global warming represents a threat to resident host populations.

TNF-alpha in bulls experimentally infected with Trypanosoma vivax: a pilot study.

There are few studies about the immune response during trypanosomosis in cattle. The objective of this research was to evaluate the effect of experimental infection with Trypanosoma vivax (T. vivax) on serum levels of TNF-alpha in bulls and its relationship to hematocrit, body temperature and parasitemia. Two adult crossbred bulls were infected experimentally with T. vivax and two were used as controls. The bulls were evaluated during a 64 day period in terms of temperature, hematocrit, and parasitemia. Serum TNF-alpha levels were determined by ELISA, using an antibody specific for bovine. TNF-alpha in serum began rising on the seventh day after infection and reached a peak on day 40 of post-infection, then dropped. The lowest hematocrit levels corresponded to the upper levels of TNF-alpha, for each animal. In conclusion, the experimental infection of cattle with T. vivax promotes the release of TNF-alpha, demonstrating a pro-inflammatory immune response to this hemotropic parasite. Moreover, the lowest hematocrit levels coincide with high concentrations of TNF-alpha, suggesting that this cytokine can be linked to the observed anemia during the course of infection by T. vivax in cattle.

Pathogenic action of Plasmodium gallinaceum in chickens: brain histology and nitric oxide production by blood monocyte-derived macrophages.

Plasmodium infection causes major losses to animal and human populations. The characterization of experimental malaria models is needed for a better understanding of disease mechanisms and the development of new treatment protocols. Chickens infected with Plasmodium gallinaceum constitute an adequate malaria model due to the phylogenetic proximity of this parasite to human Plasmodium as well as similarities in disease manifestation, such as cerebral malaria. The aim of the present study was to further characterize the experimental chicken model with an emphasis on clinical manifestations, cerebral histology and nitric oxide (NO) produced by macrophages. The results revealed that mortality was correlated to higher parasitemia. Parasitemia was positively correlated to temperature and negatively correlated to haematocrit value. Brain histology of infected birds revealed inflammatory infiltrates and blocked microvasculature. Macrophages derived from blood monocytes produced NO after activation, with a higher production positively correlated to parasitemia. These results characterize histological aspects of chicken brain malaria and demonstrate the activation of the innate immune system caused by the infection in chickens.

Early onset and long lasting protection in pigs provided by a classical swine fever E2-vaccine candidate produced in the milk of goats.

For vaccination against classical swine fever virus (CSFV), it is strongly desirable to induce a rapid and long lasting protection. At present, only live attenuated CSFV vaccines have shown early onset of protection, differing with the recombinant subunit-based vaccines reported so far. Recently, a new vaccine formulation based on E2 envelope viral glycoprotein produced in the milk of goats (E2his) has been shown to induce a highly protective response in pigs against CSFV infection. Pigs immunized with a single dose of this vaccine candidate, formulated as a water-in oil emulsion, elicited an effective response against CSF as early as 7 days post-vaccination. No severe CSF clinical signs were observed and no animals died although the challenge dose was 10(5)PDL(50) of a highly pathogenic CSFV strain. Noticeably, this response completely prevented CSFV infection in pigs when they were challenged under the same conditions 2 weeks after a single dose of the recombinant E2his vaccine formulation. A schedule consisting of a primary immunization with the same vaccine candidate, followed by a booster dose 2 weeks later induced a highly protective response against CSFV infection for as long as 9 months post-vaccination. These promising results demonstrate by far the feasibility of using the E2his-based vaccine in regional programs for preventing and controlling CSF.

Partial protection against tissue cysts formation in pigs vaccinated with crude rhoptry proteins of Toxoplasma gondii.

A vaccine containing crude Toxoplasma gondii rhoptry proteins incorporated in the immunostimulating complexes (ISCOM) adjuvant was tested in pigs for protecting against tissue cyst formation. For this, 38 mixed breed pigs were divided into four groups, G1 (vaccinated challenged, n=10) received two doses (100 microg/dose) of the rhoptry vaccine at days 0 and 21, G2 (vaccinated challenged, n=10) received viable tachyzoites (7 x 10(7)) of the RH strain at day 0, G3 (unvaccinated challenged, n=10) and G4 (unvaccinated unchallenged, n=8). Pigs were challenged with 4 x 10(4) VEG strain oocysts 57 days later. The G1 pigs produced high IgG antibody levels in the indirect enzyme-linked immunosorbent assay (ELISA) after the second dose of rhoptry vaccine, but were not clinically protected against a high dose oocyst challenge. Partial protection was observed in G1 at the chronic phase of infection, when compared with G3. Pigs in group 2 developed high antibody levels and were protected against clinic signs. T. gondii was not detected in two (G1) and three (G2) pigs by mouse bioassay. The results indicate partial protection in pigs vaccinated with a rhoptry vaccine.

Circadian responses to endotoxin treatment in mice.

We tested the ability of Escherichia coli lipopolysaccharide (LPS) to phase-shift the activity circadian rhythm in C57Bl/6J mice. Intraperitoneal administration of 25 microg/kg LPS induced photic-like phase delays (-43+/-10 min) during the early subjective night. These delays were non-additive to those induced by light at CT 15, and were reduced by the previous administration of sulfasalazine, a NF-kappaB activation inhibitor. At CT 15, LPS induced c-Fos expression in the dorsal area of the suprachiasmatic nuclei (SCN). Our results suggest that the activation of the immune system should be considered an entraining signal for the murine circadian clock.

Fiebre en el recién nacido durante su estancia en el alojamiento conjunto / Fever in neonates of mother-baby's rooming-in

Introducción. Existe controversia en cuanto a las causas de fiebre en el período neonatal, algunos autores proponen que la principal causa es la infección y otros la deshidratación. El objetivo del presente trabajo fue conocer la incidencia y causas de fiebre en el recién nacido, en un Servicio de Alojamiento Conjunto. Material y métodos. Se incluyeron a todos los recién nacidos con fiebre, manejados en el Alojamiento Conjunto, durante el período de un año. En todos se buscaron datos clínicos y de laboratorio de infección y deshidratación. En pacientes de alto riesgo se tomaron cultivos y se inició tratamiento antibiótico. En caso de deshidratación se dio suplemento con fórmula láctea. Resultados. Ochenta y cinco niños presentaron fiebre, 81 por ciento presentaron sólo un evento. Se demostró deshidratación en 75 pacientes y en 16 se sospechó septicemia y sólo en un caso se logró comprobar; al aislar el germen causante (Klebsiella sp) en cultivos de sangre y orina. Conclusión. Los resultados sugieren que cerca de 1 por ciento de los niños en Alojamiento Conjunto presentan fiebre y la causa principal es la deshidratación