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Two 16 mm color films were made to help fill a general need for instructional motion pictures in the area of Parasitology. One film "Haemonchus contortus, a Sheep Stomach Worm," deals with a nematode parasite of sheep, showing all stages of its external development and including a time-lapse sequence of the embryonation of the egg. The other film, "Some Parasites of Freshwater Fishes," shows six parasites; Ichthyophthirius multifiliis, Cotylurus erraticus, Dactylogyrus sp., Lernaea cyprinacea, Trichodina sp., and Diplostomum spathaceum for the first time in motion pictures. The films were photographed through a Wild dissecting scope and a Reichert Universal Camera Microscope, employing the techniques of brightfield, darkfield, phase contrast and Nomarski interference microscopy. The films are available from the Parasitology Laboratory of the Department of Zoology at Brigham Young University.

No description available.

No description available.

The objectives were (1) to survey the helminthfauna of the beaver, <i>Castor canadensis</i>, collected in western Maryland, particularly Garrett County, (2) to relate the helminth infections to sex, age, weight, and general condition of the beaver, and (3) to record any evidence of gross pathology involving helminths. A sample of 63 beaver, 31 males and 32 females, was obtained from Garrett, Alleghany, and Washington Counties in Maryland through fur sealing stations and the University of Maryland Natural Resources Institute at LaVale. Five helminths were found. <i>Travassosius americanus</i> infected 98,4%; <i>Castorstrongylus castoris</i>, 96.8%; <i>Stichorchis subtriquetrus</i>, 50.8%; <i>Trichostrongylus</i> sp., 36.5%; and <i>Gongylonema</i> sp., 11.1%. The unknown <i>Trichostrongylus</i> species is probably a new host record, while the <i>Gongylonema</i> sp. confirms a tentative description by another researcher in 1916 who speculated on the description of another researcher from an 1896 report. The 63 beaver surveyed were infected with at least one helminth, with a mean number of worms per infection of 220.49 (±67.52). Infections ranged between 8 and 837 helminths. The combined number of helminths per infection decreased with age; the sex had little effect, except for <i>S. subtriquetrus</i> where the rate was slightly greater in females (59%) than in males (42%). The 1½ to 3 year old beaver appear to have higher mean numbers of worms per infection with <i>T. americanus</i> and <i>C. castoris</i> than do younger or older hosts. <i>Gongylonema</i> sp. Was more prevalent in older beaver where they had a greater mean number of worms. The males and females of the helminth occurred in the esophagus of the beaver embedded parallel to each other in zipper-like burrows which caused severe irritation of the mucosal lining. <i>Gonglyonema</i> sp. Appeared to be the only helminth which had obvious pathology connected with its presence in beaver. / M.S.

The socio-economic and geographical distribution of malaria overlaps with that of many parasitic helminths and in these areas co-infections are common. Co-infection with helminths can influence disease outcome causing either exacerbation or amelioration of malaria. Understanding the complex host-parasite interactions that lead to these different disease outcomes is important for the success of control programmes aimed at these parasites. The immune system has evolved diverse types of response (e.g. T-helper 1 (Th1) and T-helper 2 (Th2)) to efficiently combat infection with ‘microparasites’ and helminths respectively. When faced with co-infection however, the need for the host to multitask means it must manage these counter-regulatory responses. In this study a murine model of malaria-hookworm (Plasmodium chabaudi- Nippostrongylus brasiliensis) co-infection was utilised to investigate how changes in T-helper bias affect malaria disease outcome. Antibody isotypes were used as indicators of Th1/Th2 bias and revealed that helminth co-infection reduced the malaria-specific Th1 response. Counter-intuitively this resulted in ‘protection’ from malaria with co-infected mice having reduced peak P. chabaudi parasitaemia and suffering less severe anaemia. In addition to providing a measure of Th1/Th2 bias, analysis of antibody responses revealed the occurrence of cross-reactive antibodies. The potential for these crossreactive antibodies to influence disease outcome was investigated but in this murine model resource-mediated mechanisms of parasite regulation appear to be responsible for the ‘protection’ that co-infection affords. The question of why cross-reactive antibodies are produced has important immunological and ecological implications. Cross-reactive responses may arise through some physiological constraint on the immune mechanisms that usually result in antibody-specificity. However experiments designed to investigate if the specificity of antibodies is constrained by availability of antigen suggest that this is not the case in the model system used here. There is also the possibility that production of cross-reactive antibodies represents an evolutionary optimal strategy for a host faced with unpredictable exposure to a variety of parasites. However a major finding of this study indicates these two taxonomically distinct parasite species share antigens, which in itself is crucial to understanding host-parasite interactions in a co-infection setting. The main findings of this thesis are relevant to co-infection studies in general and the implications for both evolutionary and applied biology are discussed.

The Hygiene Hypothesis and Old Friends Hypothesis focus attention on the coevolutionary relationship between humans and pathogens, positing that reduced pathogen exposure in economically developed nations is responsible for immune dysregulation and associated increases in chronic inflammation, allergy, and autoimmunity. Despite progress in testing these ideas, few studies have examined these relationships among populations undergoing the transition from traditional to more market-based lifestyles. The present study tests relationships between economic development and social change, altered infectious disease exposure, and immune function among the Shuar forager-horticulturalists of Amazonian Ecuador, a population undergoing rapid economic change associated with increased market participation. Using stool samples to assess soil-transmitted helminth (STHs; parasitic intestinal worms) burden, dried blood spot measurement of the inflammatory marker C-reactive protein (CRP), and interviews to evaluate level of market integration (MI; the suite of social and cultural changes associated with rapid economic development) and disgust sensitivity, this dissertation tests the Hygiene and Old Friends Hypotheses. The first study tests relationships between STH exposure and MI, using geographic location in relation to the regional market center as a proxy for MI. This study documents lower rates of STHs in people living in more market integrated regions. The second study tests the coevolutionary role that STHs and other pathogens have played in shaping human psychology and behavior. Findings suggest that pathogen exposure has acted as a selective pressure, resulting in evolved disgust sensitivity toward pathogen related stimuli. This study provides evidence that disgust sensitivity is calibrated to local environments, acting to decrease STH exposure. The third study tests the role of STHs in immune function. CRP was positively related to age in uninfected individuals. No relationships existed for more traditionally living or infected individuals. These findings suggest that STH exposure may decrease the risk of developing chronic inflammation and associated diseases with advancing age. These studies provide support for the idea that STHs provide stimuli that decrease chronic inflammation, suggesting that altered intestinal microflora in developed nations may be partially responsible for the development of chronic inflammatory disorders like allergy and autoimmunity. This dissertation includes previously published and unpublished coauthored material.

Orientador: Ricardo Velludo Gomes de Soutello / Resumo: O objetivo do presente trabalho foi avaliar o grau de verminose, ganho de peso e parâmetros hematológicos de 45 bezerros, da raça Nelore, fêmeas e machos contemporâneos, oriundos de matrizes do mesmo rebanho previamente classificadas por diferentes níveis de infecção parasitária, sendo avaliados dos 3 aos 15 meses de idade. Os animais foram divididos em grupos conforme a classificação de suas mães, sendo filhos de resistentes (G1), resilientes (G2) e susceptíveis (G3). Realizaram-se coletas de fezes a cada 28 dias para a contagem de ovos por grama de fezes (OPG), coprocultura e identificação das larvas. As pesagens dos animais foram realizadas a cada 28 dias, a partir do desmame e as coletas de sangue foram realizadas no início e no término do experimento para determinar o volume globular, proteína plasmática total e contagem de eosinófilos do sangue. O resultado obtido para a contagem de OPG aos três meses de idade demonstrou que não houve diferença significativa (P<0,05) entre G1, G2 e G3, tanto dos machos como das fêmeas. No período de três a oito meses de idade, o OPG dos bezerros machos também não apresentou diferença entre os grupos, já as bezerras filhas de vacas previamente classificadas como susceptíveis (G3) apresentaram um OPG superior em relação às filhas das resistentes e resilientes (G1 e G2). Na média geral (machos e fêmeas) das contagens de ovos também observaram-sevalores superiores nos grupos dos animais filhos de vacas susceptíveis. Após o desmame, o OPG mé... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to evaluate the degree of worms, weight gain and haematological parameters of 45 young cows, Nelore females and contemporary males, from breeders from the same herd previously classified by different levels of parasitic infection, and evaluated since 3 until 15 months of age. The animals were divided into groups according to the classification of their mothers, and puppies of resistant (G1), resilient ( G2 ) and susceptible (G3). Fecal samples was made every 28 days for counting eggs per gram of feces (EPG), coproculture and identification of larval forms. The weights of animals were taken every 28 days from weaning, and blood samples were taken at the beginning and at the end of the experiment, to determine the , total plasma protein, blood corpuscule,blood count of eosinophils. The results obtained for the EPG by three months of age, showed no significant differences (P <0.05) between groups 1, 2 and 3, both males and females. During three to eight months of age, the OPG of male young cows, also showed no difference between the groups since the young cows daughters of previously classified as susceptible (G3) had a higher OPG regarding the daughters of resistant and resilient (G1 and G2). On the average (males and females) of egg counts were also observed higher values in the groups of young from animals susceptible cows. After weaning, the overall average OPG and OPG average of females continued to show (P<0,05) in G1 and G2 with respect to ... (Complete abstract click electronic access below) / Mestre

Background: Despite the acknowledged importance of economic assessments for public health interventions at the human-animal-ecosystem interface, there are currently limited economic methodologies for doing so. In this thesis studies were undertaken to ascertain the economic impact of interventions to control trypanosomiasis and taeniasis/cysticercosis in south-east Uganda and northern Lao PDR respectively. Also, in Uganda studies were done to find out if demand of draft cattle would be an important economic driver for spreading trypanosomiasis due to inter-district trade. Method: In Uganda, a one year recall cross-sectional baseline survey and an 18 month longitudinal survey of 660 households was conducted; to determine the benefits and changes due to restricted application of deltamethrin insecticide to only the legs, belly and ears of cattle. During the 18 month study, the households participating in the study were divided into six regimes depending on the type of intervention done in their cattle and these were; diminazine injection only, deworming only, no treatment and those had 25%, 50% and 75% of the total village cattle sprayed. Thus, the first three regimes were those households that had their cattle not sprayed with insecticide at all as opposed to the last three. Additionally, cattle trade data was collected for network and value chain analysis in all markets in Tororo and Namutamba districts from 199 cattle traders. In northern Lao PDR, stochastic modelling was done to determine the burden of neurocysticercosis associated epilepsy and soil transmitted helminthes. A cross-sectional study was carried out in 49 households, focusing on the prevalence of cysticercosis and soil transmitted helminths before and after a twelve month intervention to control a hyperendemic focus of Taenia solium. The village data was then extrapolated to the wider northern Lao PDR population. Results: The Uganda study indicated that the restricted application of deltamethrin in cattle induced change of USD 31 per head of adult bovine per year; this was the change in income that directly occurred due to restricted spraying of cattle with deltamethrin. During the intervention period, the annual difference in income between those households that had their cattle sprayed using restricted application protocol and those that did not was USD 123; and this was significant (t= 7.18, p= < 0.001). Analysis of variance using households that had their cattle receive no treatment as control showed that restricted application of deltamethrin significantly increased household income compared to diminazine aceturate injection and deworming of cattle only. The incremental benefit cost ratio of spraying 0% to 25% of the cattle was found to be the highest (16:1) compared to spraying 25% to 50% (3:1) and 50% to 75% (1:1) of the cattle. Cattle trade network and value chain analysis revealed that the key cattle markets from which trypanosomiasis is likely to spread into Tororo District are Molo, Namutumba and Soroti. Also, it was found that the risk of spread of human African trypanosomiasis from south-east to north-west Uganda is high due to the increased demand for male cattle for draft work. In northern Lao PDR, 5,094 (95% CI: 25.6-28,940) DALYs were estimated to be imposed annually due to Taenia solium associated epilepsy, with 446.4 (95% CI: 2.2- 2,536) DALY imposed per 100,000 person-years. Due to the high benefits to pig production, the net monetary cost per DALY averted for simultaneously controlling T. solium, soil transmitted helminthes and classical swine fever was only USD 14, which fell to USD 11 if the separable cost method were applied. If the intervention did not target pigs, then the cost per DALY averted was USD 44; well below the current standard for ’very cost effective ‘of the 1 year’s per capita GDP. Conclusion: This study provided empirical evidence for evaluating the impact of quantifying the benefits of controlling zoonotic diseases in the livestock sector (Uganda case study) and in both livestock and human health populations (Lao PDR case study); this economic assessment approach can be used for planning future integrated health interventions. The results of this study support the policy of preventing the spread of infection by spraying at least 25% of the cattle using RAP, as well as injecting all cattle in key livestock markets in south east Uganda with diminazine aceturate to prevent HAT. In northern Lao PDR, simultaneous control of T. solium, soil transmitted helminths and classical swine fever is the most cost-effective approach. There are still difficulties in incorporating human and animal parameters into a single analytical framework; consequently there is a need to adapt the approaches undertaken in this study to the analysis of other zoonotic diseases in different settings to improve on their robustness.

Parasitic helminths infect millions of people and animals worldwide. A key feature of their lifecycle is the longevity of survival within a single host, which is often attributed to the ability of the parasite to divert or modulate the immune response against it. The excretory-secretory (ES) products released by helminths are of interest as the mediators of such immunomodulation. Heligmosomoides polygyrus is an excellent model of gastrointestinal (GI) helminth infection in rodents, and has been used here to investigate several aspects of the immune response, and the manipulation of these, in mice. Firstly, the roles of B cells and antibodies in infection with H. polygyrus and towards the adult ES (HES) were investigated. Using several B cell-deficient mouse strains, a minimal effect on immunity to primary infection with H. polygyrus was demonstrated. However, primary infection serum binds to a select set of highly immunodominant components of the complex protein mixture of HES, which were identified as venom allergen-like proteins (VALs). Utilising four strains of mice that vary in their resistance phenotype to H. polygyrus, several aspects of immunity towards the worm were investigated. Increased levels of markers of alternatively activated macrophages, which are a key component of the granulomatous inflammatory response around invading H. polygyrus larvae, were found in the most resistant strains, SJL and BALB/c. Depletion of macrophages, by administration of clodronate, severely disrupted the granuloma and parasite clearance. Numbers of innate lymphoid cells and the subsequent Th2 response, specificity range and titre of antibody, and activation of regulatory T cells all correlate with a resistant phenotype. A deficiency in the cytokine macrophage migration inhibitory factor (MIF) renders a resistant BALB/c mouse completely susceptible to infections with H. polygyrus, and Nippostronygylus brasiliensis, an acute model of GI helminth infection. This is accompanied by a failure to induce both ILCs and an early myeloid-derived cell population upon infection. The influx of alternatively activated macrophages around larvae in the mucosa of the small intestine is delayed in MIF-/- mice, although all immunological parameters are comparable to wild-type by day 14 post-infection. The susceptible phenotype of MIF-/- mice can be replicated using a chemical inhibitor of MIF in BALB/c mice. Finally, the previously documented transforming growth factor-β (TGF-β) activity of HES was dissected out further using two methods of fractionation. Distinct fractions with TGF-β activity were subjected to mass spectrometry to identify protein components that could be potential candidates for this activity.