Comparison of gastrointestinal parasite communities in vervet monkeys

Globally, habitat degradation is accelerating, especially in the tropics. Changes to interface habitats can increase environmental overlap among nonhuman primates, people, and domestic animals and change stress levels in wildlife, leading to changes in their risk of parasite infections. However, the direction and consequences of these changes are unclear, since animals may benefit by exploiting human resources (e.g., improving nutritional health by eating nutritious crops) and decreasing susceptibility to infection, or interactions with humans may lead to chronic stress and increased susceptibility to infection. Vervet monkeys are an excellent model to understand parasitic disease transmission because of their tolerance to anthropogenic disturbance. Here we quantify the gastrointestinal parasites of a group of vervet monkeys (Chlorocebus aethiops) near Lake Nabugabo, Uganda, that frequently overlaps with people in their use of a highly modified environment. We compare the parasites found in this population to seven other sites where vervet monkey gastrointestinal parasites have been identified. The vervets of Lake Nabugabo have the greatest richness of parasites documented to date. We discuss how this may reflect differences in sampling intensity or differences in the types of habitat where vervet parasites have been sampled.     

Changes in the spleen of the channel catfish Ictalurus punetatus Rafinesque indueed by infection with Aeromonas hydrophila

Abstract. A virulent, 2,3-butanediol positive culture of Aeromonas hydrophila , subspecies hydrophila , was fed or injected intraperitoneally into channel catfish. The positive infection and tissue involvement were monitored by the 2,3-butanediol test with tissue homogenate enriched with a buffered nutrient broth containing dextrose. The results revealed that the fish infected orally showed very little or no spleen involvement. Fish infected intraperitoneally, however, showed spleen involvement in a very short time, accompanied by the rapid onset of an acute systemic infection.
Light and electron microscope studies of the spleen revealed that the pathogenic bacteria were mainly located within the reticular sheath of the ellipsoids and only sparsely in the surrounding regions, and that intense phagocytic activity of macro-phages had taken place in the ellipsoids. It was also observed that the phagocytized bacteria divide extracellularly, and probably intracellularly, resulting in the destruction of the endothelial and reticular cells of the ellipsoids. This finding substantiates the cytolytic and fibrolytic capacities of A. hydrophila for destroying host defence systems and may contribute to its invasive powers. Other cytological changes in cells in spleen after infection are described, and the resistance of A. hydrophila to intracellular enzymatic digestion by the macrophages is discussed.     

Is intraspecific variation in diet and morphology related to environmental gradients? Exploring Liem's paradox in a cichlid fish

Interspecific studies have demonstrated that trophic morphology and ecology are not always tightly matched: a phenomenon rarely reported at the intraspecific level. In the present study, we explored relationships among diet, morphology and the environment in a widespread cichlid fish, Astatoreochromis alluaudi (Pellegrin 1904), from 6 sites in southern Uganda to test for evidence of eco-morphological matching at the interdemic level. Previous studies of Astatoreochromis alluaudi have demonstrated developmental plasticity in trophic morphology in response to diet: a mollusk diet produces specimens with large pharyngeal jaws and muscles, whereas a soft-food diet produces smaller pharyngeal jaws and corresponding changes in musculature. Sites were chosen to maximize variability in environmental variables that might directly or indirectly affect trophic morphology. We found significant differences in pharyngeal jaw and muscle morphology among populations. Similarly, we found differences in diets among sites: mollusks were found in the stomachs of fish from only 2 populations sampled, despite the presence of mollusks in 5 of the 6 sites. Although trophic morphology did match the observed diet in 2 sites, diet did not correlate with either morphology or environmental variables across sites, nor were environmental variables correlated with morphological variation among sites. These results suggest that mismatch can occur among different populations of a single species for reasons such as seasonality in resources, developmental plasticity and/or complex indirect interactions. Intraspecific mechanisms should be further studied in order to better understand the complex relationships between morphological specialization and ecological generalization.     

Cardiopulmonary effects of ephedrine in halothane-anesthetized horses

The cardiopulmonary effects of intravenous (i.v.) administration of the sympathomimetic drug ephedrine during two different levels of halothane anesthesia [end-tidal concentration of 1.37% (light anesthesia) and 2.1% (deep anesthesia)] were studied in eight horses. Anesthesia was induced and maintained using only halothane in O2. Ventilation was controlled to maintain a Paco2 of 38-42 mmHg. Following instrumentation and stabilization of the horse at the halothane concentration being studied, baseline measurements of cardiac output (Q), arterial blood pressure (AP), pulmonary artery pressure, heart rate, Pao2, Paco2 and pH were made. Ephedrine was then administered (0.06 mg/kg i.v.) and these measurements repeated at 10, 20, 30, 45 and 60 min after injection. At both doses of halothane there was a significant (P less than 0.05) increase in Q, stroke volume (SV), and systolic AP following ephedrine administration. In addition, at 2.1% halothane, ephedrine administration resulted in a significant (P less than 0.05) increase in mean AP and Pao2 and a decrease in total peripheral resistance. The increase in systolic AP, Q, and SV was significantly (P less than 0.05) greater at 2.1% halothane than at 1.37% halothane. Ephedrine administration to horses during both light and deep halothane anesthesia results in an increase in AP that is due to an increase in Q and SV.     

A comparison of stress in surgically and non-surgically mulesed sheep

Summary A comparison has been made in 9- to 10-month-old castrated male Merino sheep of the changes in plasma total cortisol concentration and behaviour after being treated by either the modified Mules operation or by topical application of a quaternary ammonium compound to achieve non-surgical mulesing. After surgical mulesing, plasma total cortisol concentration increased immediately and rapidly and reached a peak value in 15 minutes, whereas after non-surgical treatment an immediate rise did not occur, but a similar peak value was observed in blood samples collected 24 hours after treatment. The concentrations were lower in both groups at 48 hours. Likewise postural changes indicative of discomfort were immediately apparent in the surgically treated sheep, but not until 3 to 4 hours later in those treated non-surgically. Arena testing revealed that a lasting aversion to the person who restrained them during treatment developed in the surgically mulesed sheep, but not in those treated non-surgically. The non-surgical procedure did not create large open wounds, as did the surgical operation, but still achieved similar enlargement of the bare area on the breech, and healing was quicker in the non-surgically treated sheep.     

The incidence of Fusarium moniliforme on maize from Central America, Africa and Asia during 1992–1995

Samples of maize seed were obtained from countries in Central America, Africa and Asia and assessed for fungal infection. Fusarium spp. were the largest single group of fungi present, and from these Fusarium moniliforme was the species most frequently isolated. Other fungi, including Stenocarpella (Diplodia) maydis , S. macrospora and Acremonium strictum , were also present in significant numbers. Isolates of F. moniliforme were characterized for mating populations, using RAPDs, and a number of isolates, taken at random from those assigned to specific mating groups, were also confirmed by crossing. Isolates were also characterized for fusaric acid production and significant differences in fusaric acid production were detected between isolates from different countries and regions within countries. A detailed analysis of isolates from one country, Kenya, was undertaken. The importance of the pathogens is discussed in relation to human, animal and seed health and quarantine regulations, and plant breeding objectives.