Bactericidal activity of lachrymal secretion and complement system in copper deficient bovines.

Copper deficiency in humans and animals has been related to increased susceptibility to infections. Neutrophils are one of the most studied components of the immune response; however, to the best of our knowledge, other defenses of the innate immune system have not been analyzed in copper-deficient animals. Our previous studies in copper-deficient bovines have shown increased susceptibility to infectious keratoconjunctivitis, an ocular disease caused by Moraxella bovis. The objective of this work was to evaluate the bactericidal activity of lachrymal secretion and complement system, two main mechanisms of the innate immune response against M. bovis, in copper-deficient cattle. Our results indicate that copper deficiency has no effect on bactericidal activity of complement system and lachrymal secretion against M. bovis in calves. Other components of local and systemic ocular defense mechanisms that could explain the increased susceptibility to infectious keratoconjunctivitis observed in copper-deficient bovines should be investigated.

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains.

Shigatoxigenic Escherichia coli (STEC) strains are worldwide zoonotic pathogen responsible for different cases of human disease including hemolytic uremic syndrome (HUS). Transmission of STEC to humans occurs through the consumption of food and water contaminated by faeces of carriers and by person-to-person contact. The objective of this study was two-fold: (1) to investigate whether synanthropic rodents are possible reservoirs of STEC in the urban area and (2) whether a particular genus out of synanthropic rodent is the principal carrier of STEC. One hundred and forty-five rodents were captured in Buenos Aires City. Screening for stx1/stx2 and rfbO157 was done by PCR from the confluence zone. STEC isolates were further characterized with biochemical tests by standard methods. Additional virulence factors (eae, ehxA, and saa) were also determined by PCR. Forty-one of the rodents were necropsied and sample of kidney and small and large intestine were taken for histopathological diagnosis. The samples sections were stained with hematoxylin-eosin, and observed by light microscopy to evaluate the systemic involvement of these species in natural infections. STEC was isolated from seven out of 27 suspect animals at screening. The following genotypes were found in the STEC strains: stx1/stx2/ehxA (1), stx2 (4), stx2/ehxA (1), stx2/ehxA/eae (1). Neither gross nor microscopic lesions compatible with those produced by Shiga toxin were observed in the studied organs of necropsied rodents. The bivariate analysis including the 145 rodent's data showed that the isolation of STEC is associated positively to Rattus genus. This synanthropic species may play a role in the transmissibility of the agent thus being a risk to the susceptible population. Their control should be included specifically in actions to dismiss the contamination of food and water by STEC in the urban area, as additional strategies for epidemiological control.

Pharmacokinetics and pharmacodynamics of interferon beta 1a in Cebus apella.

BACKGROUND: Recombinant human interferon (hIFN beta) is indicated for the treatment of multiple sclerosis. Its effect presents species restriction, thus lacking biological activity on most mammals. Although there have been previous studies of the pharmacology of INF beta in Old World primates, no data exists on New World primates. Therefore, we explored its effect on Cebus apella, a New World monkey, describing the pharmacology of this molecule when injected by subcutaneous route in this species. METHODS: Safety, pharmacokinetics and pharmacodynamics of IFN beta were evaluated in nine Cebus apella individuals. RESULTS: A single subcutaneous injection of 12 x 10(6) IU of hIFN beta 1a resulted in a median AUC((0-48)) (area under the curve) of 14.82 ng/ml, a C(max) (maximum plasma concentrations) of 1.51 ng/ml and a T(max) (time to achieve maximum plasma concentrations) of 3 h. IFN beta was biologically active as demonstrated by an increase in neopterin levels. There were no safety concerns. CONCLUSIONS: New World non-human primates are a suitable animal model for the study of IFN beta pharmacology.

Moraxella bovis pathogenicity: an update.

Moraxella bovis is the etiologic agent of infectious bovine keratoconjunctivitis, the most important ocular disease affecting cattle worldwide. The severity of the cases varied from eyes that exhibited mild signs to severe clinical cases with profuse lacrimation, conjunctival swelling, corneal opacity, and ulceration. Although the mortality is low, there is a high morbidity and important economic loss in terms of significant reduction in production. This paper examines aspects such as the pathogenesis of the disease and the mechanisms by which this unique bacterium is able to disrupt the corneal epithelium and cause infection.

Comparison of three diagnostic techniques for the detection of leptospires in the kidneys of wild house mice (Mus musculus)

Foram capturados 41 camundongos (Mus musculus) na região urbana, próximo à ferrovia da cidade de Santa Fé, Argentina. Os rins de cada animal capturado foram removidos para estudos bacteriológicos e histológicos. Um dos rins foi imerso em meio semi-sólido de Fletcher para isolamento de leptospiras, as quais foram serologicamente tipificadas. O outro rim foi microscopicamente examinado por coloração de cortes histológicos pela hematoxilina-eosina, impregnação pela prata e imunohistoquímica. Leptospiras pertencentes ao serogrupo Ballum foram isoladas em 16 (39%) das 41 amostras availadas. A presença do agente foi observada em 18 (44%) e 19 (46%) das 41 amostras avaliadas por impregnação pela prata e imunohistoquímica, respectivamente. Leptospiras foram detectadas em grande numero na superfície apical das células epiteliais e no lumen dos túbulos medulares e foram menos frequentemente encontradas na superficie apical de células epiteliais ou no lúmen dos túbulos corticais, o que é considerado achado raro em animais portadores. Lesões microscópicas consistindo de nefrite mononuclear intersticial focal, atrofia glomerular e descamação das células tubulares epiteliais foram observadas em 13 dos 19 animais infectados e em 10 dos 22 animais não infectados. Não houve diferença estatisticamente significativa entre presença de lesões em animais infectados e não infectados (P=0,14). As três técnicas empregadas, isolamento, impregnação pela prata e imunohistoquímica, apresentaram alta concordância (k 0,85) e não apresentaram diferenças estatisticamente significativas (P>0,05). Esse trabalho descreve a presença incomum de leptospira em rins de animais portadores, porém com esse estudo não foi possível estabelecer uma relação entre lesões e presença de leptospira.