Molecular typing of sand fly species (Diptera, Psychodidae, Phlebotominae) from areas endemic for Leishmaniasis in Ecuador by PCR-RFLP of 18S ribosomal RNA gene

Surveillance of the distribution of sand fly species is important for prediction of the risk and expansion of Leishmania infection in endemic and surrounding areas. In the present study, a simple and reliable method of typing New World Lutzomyia species circulating in endemic areas in Ecuador was established by using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique. PCR-RFLP of 18S ribosomal RNA (rRNA) genes with the restriction enzyme AfaI and subsequently HinfI successfully identified seven sand fly species in nine endemic areas in Ecuador. Although intraspecific genetic-diversity affecting the RFLP-patterns was detected in a species, the patterns were species specific. The method promises to be a powerful tool for the classification of New World Lutzomyia species.     

Lesions associated with the plexus venosus subcutaneus collaris of pigeons with chlorophacinone toxicosis

We describe lesions in 29 adult domestic pigeons (Columba livia) poisoned with chlorophacinone, an indandione anticoagulant rodenticide. Birds were found dead in the field and in dovecotes after a wide-area treatment against common voles (Microtus arvalis) based on the dispersion in the open field of wheat grain treated with 0.005% chlorophacinone. At necropsy, most pigeons showed crops full of red-colored wheat grain, extensive subcutaneous hematoma in neck and breast zones, and hemorrhages in lungs and the coelomic cavity. Chlorophacinone was determined in liver samples by high-performance liquid chromatography with ultraviolet detection, and the mean (range) concentration was 11.2 (1.48-50.1) microg/g. Pigeons have a venous subcutaneous plexus in the neck zone (plexus venosus subcutaneus collaris), which has been described as an erectile tissue with a thermoregulation function. This case report describes a relationship between the subcutaneous hemorrhagic lesions and the plexus venosus collaris.     

Magnetic resonance imaging in the diagnosis of type 1 dermoid sinus in two Rhodesian ridgeback dogs

Two cases of type 1 dermoid sinus in Rhodesian ridgebacks are described, with emphasis on the use of magnetic resonance imaging (MRI) in the diagnosis and delineation of the lesions. Magnetic resonance imaging was useful in identifying fluid-filled structures, fibrous capsules, and sinus tracts, but was not able to identify the termination of the tracts.     

Pharmacokinetics and pharmacodynamics of chlorpyrifos in male and female cattle after topical administration

The aim of this work was to study the pharmacokinetic behaviour and the inhibitory effect on acetylcholinesterase and butyrylcholinesterase activities of chlorpyrifos in male and female cattle after pour-on administration. Determination of cholinesterase activity in plasma and erythrocyte was carried out according to Ellman kinetic method. The mean baseline activities were 9338.39 ± 1331.61 and 13220.69 ± 2274.18 to acetylcholinesterase and 624.65 ± 39.32 and 641.68 ± 88.08 IU/L to butyrylcholinesterase in females and males, respectively. Acetylcholinesterase was the predominant form of cholinesterase analyzed, with low levels of butyrylcholinesterase. The basal acetylcholinesterase activities of the bulls were significantly greater than those of cows. The inhibitory effect of topical chlorpyrifos administration was lower on butyrylcholinesterase than on acetylcholinesterase. Chlorpyrifos peak plasma concentration (male:10.920 ± 4.18; female:12.12 ± 3.88 μg/L) were reached at 11.92 ± 9.19 and 8.17 ± 7.67 h in male and female, respectively. The values of area under curve were 185.96 ± 168.45 and 278.89 ± 270.00 μg·h/L and mean residence time were 13.95 ± 8.10 and 14.90 ± 9.80 h in male and female, respectively.     

Genetic diversity and phylogenetic relationships between Leishmania infantum from dogs,humans and wildlife in south‐east Spain

Leishmania infantum causes human and canine leishmaniosis. The parasite, transmitted by phlebotomine sand flies, infects species other than dogs and people, including wildlife, although their role as reservoirs of infection remains unknown for most species. Molecular typing of parasites to investigate genetic variability and evolutionary proximity can help understand transmission cycles and designing control strategies. We investigated Leishmania DNA variability in kinetoplast (kDNA) and internal transcribed spacer 2 (ITS2) sequences in asymptomatically infected wildlife (n = 58) and symptomatically and asymptomatically infected humans (n = 38) and dogs (n = 15) from south‐east Spain, using single nucleotide polymorphisms (SNPs) and in silico restriction fragment length polymorphism (RFLP) analyses. All ITS2 sequences (n = 76) displayed a 99%–100% nucleotide identity with a L. infantum reference sequence, except one with a 98% identity to a reference Leishmania panamensis sequence, from an Ecuadorian patient. No heterogeneity was recorded in the 73 L. infantum ITS2 sequences except for one SNP in a human parasite sequence. In contrast, kDNA analysis of 44 L. infantum sequences revealed 11 SNP genotypes (nucleotide variability up to 4.3%) and four RFLP genotypes including B, F and newly described S and T genotypes. Genotype frequency was significantly greater in symptomatic compared to asymptomatic individuals. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Accordingly, the phylogenetic analysis of kDNA sequences revealed three main clusters, two as a paraphyletic human parasites clade and a third including dogs, people and wildlife parasites. Results suggest that Leishmania infantum genetics is complex even in small geographical areas and that, probably, several independent transmission cycles take place simultaneously including some connecting animals and humans. Investigating these transmission networks may be useful in understanding the transmission dynamics, infection risk and therefore in planning L. infantum control strategies.     

Sperm competition and the evolution of sperm form and function in mammals

Sperm competition is a powerful selective force that has influenced many reproductive traits in males and females although additional evolutionary explanations may help to understand the diversity of mammalian reproduction. Sperm morphology varies considerably in mammals with extreme examples in several rodent lineages in which a wide range of sizes and complex head morphologies have been identified. Mammalian spermatozoa also differ in function, with swimming velocity and trajectory showing much divergence. Underlying processes mediating function have received little attention so far, but differences in timing and proportion of sperm undergoing capacitation or acrosomal exocytosis may be related to variation in signalling processes. Furthermore, energy required for sperm functions (such as motion, signalling and overall maintenance of cell integrity) can be produced and consumed, following different patterns among species and this could be the result of several selective forces. A more thorough understanding of the diversity in structure and function of sperm cells, and underlying selective forces, may help us develop better methods to assess them taking into account particulars and generalities of sperm form and performance. Such tests could then become more reliable in estimations of the impact of cryopreservation or effect of changes in the environment and their relevance for fertility.     

Carcass characteristics and meat quality of sheep fed alfalfa hay to replace Bermuda grass hay

Tropical Animal Health and Production - The objective of this study was to evaluate carcass characteristics, meat quality, and organ and viscera weight of forty male sheep, not castrated, initially...     

Comparison of serological assays for the diagnosis of canine visceral leishmaniasis in animals presenting different clinical manifestations

Three serological methods, indirect fluorescent immunoassay (IFI), enzyme-linked immunosorbent assay (ELISA) and direct agglutination test (DAT) that are commonly employed in the diagnosis of canine visceral leishmaniasis (CVL), have been assessed. A total of 234 domestic dogs, drawn from an area in the municipality of Belo Horizonte, Minas Gerais, Brazil, endemic for visceral leishmaniasis, were submitted to clinical and parasitological examinations and serological assay. Sera collected from confirmed non-infected dogs (n=20), and from dogs with other parasitic diseases including Trypanosoma cruzi (n=7), Leishmania braziliensis (n=5), Toxoplasma gondii (n=5) and Ehrlichia canis (n=3), were also included in the study. IFI presented a lower sensitivity (72%) than ELISA (95%), although the specificities of these assays were low (52 and 64%, respectively) and both exhibited cross-reactivity with sera from dogs infected with T. cruzi, L. braziliensis and E. canis. In contrast, DAT exhibited a high sensitivity (93%) and a high specificity (95%) and cross-reacted with only one serum sample derived from an E. canis-infected dog. The reproducibilities of the ELISA and DAT assays were excellent, whilst that of IFI was considered to be acceptable. The results produced by ELISA and DAT were in complete agreement, those between ELISA and IFI were at an acceptable level of agreement, whilst the concurrence between the IFI and DAT results were either acceptable or poor depending on the clinical conditions of the group of dogs examined. Since there is no readily accessible method for the diagnosis of CVL that offers 100% specificity and sensitivity, the choice of technique employed must depend on the aim of the investigation.