Schizotrypanids: the occurence of dermatitis in immunodeficiency animals infected with Trypanosoma cruzi

Congenitally athymic nude Balb/c (nu/nu) and their phenothypically normal adult and neonate littermates (nu/+), the C3H/HeN as well, were intraperitoneally infected with two strains (Y or CL) of Trypanossoma cruzi. The nude mice and the neonates developed a severe parasitaemia, the susceptible C3H/HeN also presented high level and adult Balb/c mice presented parasitaemia similar to that observed in outbred mice. Erythematous skin lesions were observed initially in infected athymic nude and neonates, being charactherized by nests of amastigotes in the dermis; in C3H/HeN infected mice no nest of parasite was observed but a low-grade inflammatory reaction was seen. In adult Balb/c or OF1 outbred mice nest was found but discreet inflammatory reaction was observed in severe infections.

Fear assessment in pigs exposed to a novel object test

The experiment aimed to study approach and locomotive behaviour as indicators of fear in a novel object test carried out in pigs. Thirty post-weaning (30 kg) and 30 finishing (90 kg) pigs were exposed to visual, auditory and olfactory novel stimuli during 2 different experiments. The facilities consisted of a test pen in which a trough was located. The trough contained chopped apples. Once the animals were trained to enter the test pen individually they were subjected to 3 different fear stimuli. These stimuli were applied in the test pen and next to the trough. The variables studied were feeding behaviour, approach behaviour (the distance and position of the animal with respect to the trough) and locomotive behaviour (general activity, reluctance to move, turning back and retreat attempts). Two groups were studied: saline and midazolam treated group. Twenty minutes before the start of the sessions, 15 post-weaning and finishing pigs received an intramuscular injection of 0.20 and 0.15 mg/kg, respectively, midazolam (Dormicum1). The saline pigs (15 animals per group) were injected with saline. The administration of midazolam increased the feeding behaviour and approaching behaviour, and reduced the locomotive behaviour. In front of the visual and olfactory stimuli post-weaning pigs showed a higher general activity than finishing pigs, but the contrary was found when the auditory stimulus was applied. The olfactory stimulus was more related to the turning back behaviour, whereas the visual stimulus was more related to retreat attempts. Although it could be concluded that reluctant to move was the most common response to the different fear stimuli applied in our study regardless of the age of animals, the combination of reluctant to move and turning back would be a good criterion to assess fear in domestic pigs. The use of midazolam as anxiolytic for studies of fear in commercial conditions in pigs is recommended.

Inter-relation of sylvatic and domestic transmission of Trypanosoma cruzi in areas with and without domestic vectorial transmission in Minas Gerais, Brazil

During the period 1980-1986, we captured triatomine bugs and mammalian reservoir hosts from sylvatic and domestic situations in different municipalities of the State of Minas Gerais. Trypanosoma cruzi was isolated from captured bugs, mammals and patients. After cultivation in LIT medium, the electrophoretic enzyme profiles were determined. We obtained atotal of 32 parasite isolates from regions with active domestic transmission, and 24 isolates form areas under control. For the first areas the results suggest introduction of T. cruzi from sylvatic habitats, through incursion of infected opossums and/or sylvatic T. sordida, which appears to have given rise to at least one acute human infection. Of particular interest is the finding of sylvatic opossums and a T. sordida nymph infected with ZB, that could indicate return of parasites from chronic human infections to sylvatic transmission cycles. For the areas under control we also interpret the results as interaction between sylvatic and domestic cycles of transmission, here through the invasion of houses by bugs carrying the Z1 zymodeme from the sylvatic environment. The Multivariate Correspondence Analysis gives a spatial description between the different parasite isolates and confirms the existence of a bridge in the opposite direction in the region with active vectorial transmission including the exporting of Z2 through the peridomestic environment into the sylvatic cycle. For the others areas this bridge corresponds especially to Panstrongylus megistus, importing Z1 into the domestic environment.

Pro-opiomelanocortin gene and melanin-based colour polymorphism in a reptile

Colour polymorphism is widespread among vertebrates and plays important roles in prey-predator interactions, thermoregulation, social competition, and sexual selection. However, the genetic mechanisms involved in colour variation have been studied mainly in domestic mammals and birds, whereas information on wild animals remains scarce. Interestingly, the pro-opiomelanocortin gene (POMC) gives rise to melanocortin hormones that trigger melanogenesis (by binding the melanocortin-1-receptor; Mc1r) and other physiological and behavioural functions (by binding the melanocortin receptors Mc1-5rs). Owing to its pleiotropic effect, the POMC gene could therefore account for the numerous covariations between pigmentation and other phenotypic traits. We screened the POMC and Mc1r genes in 107 wild asp vipers (Vipera aspis) that can exhibit four discrete colour morphs (two unpatterned morphs: concolor or melanistic; two patterned morphs: blotched or lined) in a single population. Our study revealed a correlation between a single nucleotide polymorphism situated within the 3-untranslated region of the POMC gene and colour variation, whereas Mc1r was not found to be polymorphic. To the best of our knowledge, we disclose for the first time a relationship between a mutation at the POMC gene and coloration in a wild animal, as well as a correlation between a genetic marker and coloration in a snake species. Interestingly, similar mutations within the POMC 3-untranslated region are linked to human obesity and alcohol and drug dependence. Combined with our results, this suggests that the 3-untranslated region of the POMC gene may play a role in its regulation in distant vertebrates.

Reliability of serological methods for detection of leishmaniasis in portuguese domestic and wild reservoirs

A direct agglutination test (DAT) and an immunofluorescence technique (IFAT) were compared for detection of Leishmania infantum infection in 43 dogs and five foxes from Alto-Douro and Arrábida, two known endemic areas in Portugal. In four dogs with proved canine leishmaniasis, both DAT and IFAT showed positive readings (titres >1:320 and >1:128). Of 34 samples collected from apparently healthy dogs, ten were positive by both serological tests and eight were serologically positive by one test or the other. Three foxes out of five captured in this area, scored titres indicative of leishmaniasis in both DAT and IFAT. The concordance between DAT and IFAT in all collected samples (48) was 81.25%. Considering these and previous studies in the adjacent Mediterranean areas, the seroprevalence of L. infantum infection in the canine and vulpine populations appear to be of high magnitude.

Study on the Elimination of Angiostrongylus costaricensis First Stage Larvae in the Experimental Infection of Swiss Mice

Abdominal angiostrongylosis is a nematode infection of wild rodents. Human infection may result in severe abdominal disease and has been reported from several countries in the Americas. The domestic mouse, Mus musculus, has not been found with natural infection and, like other urban rodents, should not be considered a natural host for Angiostrongylus costaricensis. Quantification of parasitic forms released for transmission may better express the coevolutionary status in parasite-host relationship. With this objective, five groups of experimentally infected Swiss mice were followed for up to 155 days post-infection (PI) days and the quantification of first stage larvae (L1) output revealed: an irregular elimination of L1 and a huge variation in the patency period (1 to 114 days) and in the number of L1 eliminated daily by individual animals (1 to 6340 L1/g). Overall mortality was 72% (range: 28% to 100%) at seven weeks PI. In conclusion, abdominal angiostrongylosis in M. musculus presents high mortality and a very variable and irregular elimination of L1 in feces.

Scanning Electron Microscopy of Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae)

Lagochilascaris minor Leiper, 1909 is a parasitic nematode with its biological cycle still unknown, even though it was found in humans, domestic and silvatic animals. Adult worms, collected by surgical drainage from a human patient from the State of Pará, Brazil, were micrographed using a scanning electron microscope. Morphological aspects of males and females such as cephalic structures, caudal papillae and cuticular patterns were analyzed and compared with the previous descriptions adding new data for the identification of this species.

Eimeria minasensis n. sp. (Apicomplexa: Eimeriidae) in the Domestic Goat Capra hircus, from Brazil

Eimeria minasensis n. sp. is described in the domestic goat Capra hircus from Brazil. Oocysts ellipsoidal are 35 x 24.5 (32-37.7 x 20.9-27.9) mm. Sporocysts elongate-ellipsoid are 15.2 x 9 (12.3-18.4 x 7.8-10.2) mm, with a Stieda body at the narrow end. Oocyst wall smooth and bilayered; outer layer about 1.2 (0.8-1.6) mm and colorless; inner layer about 0.5 (0.4-0.8) mm and dark-brown. Micropyle, a mound-shaped micropylar cap 1,6 x 8,9 (0,8-2 x7-10,2) easily dislodged; one or more oocyst polar granules present. Oocyst residuum absent. Sporocyst residuum present, composed of many scattered granules. Sporozoites elongate, lying lengthwise, "head to tail" in the sporocysts; one or two refractile globules are usually visible. Sporulation time was 120 hr at 27oC, prepatent period, 19 to 20 days and patent period 15 to 25 days. Gamonts, gametes and oocysts present in cecum and colon. Prevalence was 12.8% (6/47) in goats from Minas Gerais, Brazil.

Characterization of Trypanosoma rangeli Strains Isolated in Central and South America: an Overview

Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies comparing T. rangeli strains isolated in Santa Catarina with others isolated in Colombia, Honduras and Venezuela. The different methods used include indirect immunofluorescence and western blot assays, lectin agglutination, isoenzyme electrophoresis and random amplified polymorphic DNA analysis, triatomine susceptibility, in vitro cell infection assays, and mini-exon gene analysis.

Genetic Structure of Triatoma sordida (Hemiptera: Reduviidae) Domestic Populations from Bolivia: Application on Control Interventions

The genetic population of Triatoma sordida group 1, a secondary vector of Chagas disease in Bolivia, was studied by multi-locus enzyme electrophoresis. A total of 253 nymphal and adult specimens collected from seven neighbouring localities in the Velasco Province, Department of Santa Cruz, were processed. The relatively low genetic variability was confirmed for this species (rate of polymorphism: 0.20). The absence of genetic disequilibrium detected within the seven localities was demonstrated. A geographical structuration appears between localities with distances greater than 20 km apart. Although T. sordida presents a relatively reduced dispersive capacity, its panmictic unit is wider than compared with T. infestans. Genetic distances between T. sordida populations were correlated with geographic distance. Gene flow between geographic populations of T. sordida provides an efficient framework for effective vigilance and control protocols.

Wild Rodents as Experimental Intermediate Hosts of Lagochilascaris minor Leiper, 1909

A total of 25 specimens of Cavia porcellus (guinea pig), 5 Dasyprocta agouti (agouti), and 22 Calomys callosus (vesper mice) were inoculated with infective eggs of Lagochilascaris minor. The inoculum was prepared with embryonated eggs and orally administered to each individual animal through an esophagus probe. In parallel, 100 specimens of Felis catus domesticus were individually fed with 55-70 nodules containing 3rd-stage larvae encysted in tissues of infected rodents. Animals were examined and necropsied at different time intervals. The migration and encystment of L3 larva was observed in viscera, skeletal muscle, adipose and subcutaneous tissues from all rodents. Adult worms localized at abscesses in the cervical region, rhino, and oropharynx were recovered from domestic cats inoculated with infected rodent tissues. Through this study we can conclude that: (1) wild rodents act as intermediate hosts, characterizing this ascarid heteroxenic cycle; (2) in natural conditions rodents could possibly act as either intermediate hosts or paratenic hosts of Lagochilascaris minor; (3) despite the occurrence of an auto-infecting cycle, in prime-infection of felines (definite hosts) the cycle is only completed when intermediate hosts are provided; and (4) in the wild, rodents could serve as a source of infection for humans as they are frequently used as food in regions with the highest incidence of human lagochilascariasis.

Evaluation of two minimally invasive techniques for electroencephalogram recording in wild or freely behaving animals.

Insight into the function of sleep may be gained by studying animals in the ecological context in which sleep evolved. Until recently, technological constraints prevented electroencephalogram (EEG) studies of animals sleeping in the wild. However, the recent development of a small recorder (Neurologger 2) that animals can carry on their head permitted the first recordings of sleep in nature. To facilitate sleep studies in the field and to improve the welfare of experimental animals, herein, we test the feasibility of using minimally invasive surface and subcutaneous electrodes to record the EEG in barn owls. The EEG and behaviour of four adult owls in captivity and of four chicks in a nest box in the field were recorded. We scored a 24-h period for each adult bird for wakefulness, slow-wave sleep (SWS), and rapid-eye movement (REM) sleep using 4 s epochs. Although the quality and stability of the EEG signals recorded via subcutaneous electrodes were higher when compared to surface electrodes, the owls' state was readily identifiable using either electrode type. On average, the four adult owls spent 13.28 h awake, 9.64 h in SWS, and 1.05 h in REM sleep. We demonstrate that minimally invasive methods can be used to measure EEG-defined wakefulness, SWS, and REM sleep in owls and probably other animals.