Transmission Of Parasitic Diseases Research Articles

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.

Establishment of response system to emergency parasitic disease affairs in China

China's prevention and control of parasitic diseases has made remarkable achievements. However, the prevalence and transmission of parasitic diseases is impacted by the complicated natural and social factors of environment, natural disasters, population movements, and so on. Therefore, there are still the risks of the outbreak of emergency parasitic diseases affairs, which may affect the control effectiveness of parasitic diseases and endanger the social stability seriously. In this article, we aim at the analysis of typical cases of emergency parasitic disease affairs and their impacts on public health security in China in recently years, and we also elaborate the disposal characteristics of emergency parasitic disease affairs, and propose the establishment of response system to emergency parasitic disease affairs in China, including the organizational structure and response flow path, and in addition, point out that, in the future, we should strengthen the system construction and measures of the response system to emergency parasitic disease affairs, so as to control the risk and harm of parasitic disease spread as much as possible and to realize the early intervention and proper disposal of emergency parasitic disease affairs.

HIGH FREQUENCY OF Ascaris lumbricoides IN PUBLIC PLAYGROUNDS IN CENTRAL BRAZIL

Public playgrounds may be sources of parasite infections. This study analyzed the occurrence of intestinal parasites in playgrounds in the Federal District of Brazil (DF). Seventy sand samples were collected in 14 playgrounds distributed around the DF in 2015-2016 and were processed using the Willis and Hoffman methods. All playgrounds were contaminated with parasites. The parasites identified were Ascaris lumbricoides (33%), Strongyloides sp. (6%), Ancylostomidae (4%), Giardia sp. (4%), Trichuris sp. (3%) Toxocara sp. (3%) and Hymenolepis nana (1%). Results show the potential risk of transmission of parasitic diseases (mainly ascariasis) in playgrounds in central Brazil.

Prevalensi Trichuriasis pada Anak di Sekolah Dasar Negeri Harapan Maju: Studi Kasus di Kabupaten Tanah Bumbu Provinsi Kalimantan Selatan

Trichuriasis is an infectious disease due to nematode Trichuris trichiura . Trichuriasis prevalence is the highest among infectious diseases due to other parasitic worms in Indonesia. Elementary school-age children at high risk of this disease. This study aimed to determine the prevalence of trichuriasis in children of elementary school age in Tanah Bumbu regency. This research was conducted in 2015 with cross sectional design, using purposive sampling method. A total of 250 children from Harapan Maju Elementary School was selected as samples, their stools were examined with native method (direct). The results showed the parasitic worms were T . trichiura, Ascaris lumbricoides, hookworm and Enterobius vermicularis. The prevalence of T . trichiura was the highest, as many as 32 children (12.8%) were infected from a total of 250 samples. T . trichiurainfection was found in the form of a single and mixed infection with other parasitic worms. Trichuriasis more commonly found in girls and boys aged 10-12 years. Helminthic treatment needs to be done selectively for infected children using the broad-spectrum drugs. Behavioral and environmental factors of patients with intestinal helminths need to be identified spesificly . Furthermore it would be analyzed to determine the factors involved in the transmission of parasitic diseases. In order to prevent the transmission within the school need the improvements of school infrastructure such as the provision of public hand washing, covered trash bin, paving or cemented for the school yard

Coprological survey of parasites of free-ranging jaguar (Panthera onca) and puma (Puma concolor) inhabiting 2 types of tropical forests in Mexico

This study presents a coproparasitological survey of free-ranging jaguars (Panthera onca) and pumas (Puma concolor) inhabiting 2 types of tropical forest in southeastern Mexico. We examined 167 fecal samples (68=jaguar; 33=puma; 66=unidentified large felids), and identified 16 parasitic taxa, 56% of which were nematodes. We compared parasite community composition and prevalence between host species and forest types, and found that parasitic communities of jaguar and puma were more similar between host species in the same forest type than among conspecific hosts inhabiting different forest types. Possible determinants for the observed patterns could include ecosystem differences and host evolutionary history, as well as disparate diet and habitat use of these 2 felines. Further studies are needed for a more accurate estimation of the parasitic community composition of these felines, and for a better comprehension of the effects that habitat perturbation could have on the ecology and transmission of parasitic diseases, and the related consequences for the conservation of wild felines.

Modeling impacts of climate change on the potential distribution of the carcinogenic liver fluke, Opisthorchis viverrini, in Thailand.

Global climate change is now regarded as imposing a significant threat of enhancing transmission of parasitic diseases. Maximum entropy species distribution modeling (MaxEnt) was used to explore how projected climate change could affect the potential distribution of the carcinogenic liver fluke, Opisthorchis viverrini, in Thailand. A range of climate variables was used: the Hadley Global Environment Model 2-Earth System (HadGEM2-ES) climate change model and also the IPCC scenarios A2a for 2050 and 2070. Occurrence data from surveys conducted in 2009 and 2014 were obtained from the Department of Disease Control, Ministry of Public Health, Thailand. The MaxEnt model performed better than random for O. viverrini with training AUC values greater than 0.8 under current and future climatic conditions. The current distribution of O. viverrini is significantly affected by precipitation and minimum temperature. According to current conditions, parts of Thailand climatically suitable for O. viverrini are mostly in the northeast and north, but the parasite is largely absent from southern Thailand. Under future climate change scenarios, the distribution of O. viverrini in 2050 should be significantly affected by precipitation, maximum temperature, and mean temperature of the wettest quarter, whereas in 2070, significant factors are likely to be precipitation during the coldest quarter, maximum, and minimum temperatures. Maps of predicted future distribution revealed a drastic decrease in presence of O. viverrini in the northeast region. The information gained from this study should be a useful reference for implementing long-term prevention and control strategies for O. viverrini in Thailand.

Malacological survey and geospatial distribution of <i>Indoplanor bisexutus</i> (Deshayes, 1934) and <i>Lymnaea natalensis</i> (Krauss 1848) snail vectors of trematode parasites, in Abeokuta, south-western, Nigeria

Vector snails of trematode parasites are important because of their role in the transmission of parasitic diseases. However, information on the diversity and distribution of snail hosts in Abeokuta area of Ogun State is scanty. Snails were collected from 31 water bodies including streams, rivers and dams on a monthly basis for six months. The snails were identified using shell morphology and examined for cercariae shedding. Collection sites were geo-referenced. Environmental data, Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), rainfall and Land cover corresponding to these locations were derived from Moderate resolution Imaging Spectroradiometer (MODIS). Binary logistic regression analysis was used to create spatial maps and predictive model map for snail species distribution. A total of 87 vector snails were collected; Lymnaea natalensis 65 (74.71%) and Indoplanor bisexutus 22 (25.29%).Nine out of 22I. exutus collected shed microcercouscercariae. Infected I. exutus, intermediate snail host of Schistosoma nasale, a cattle schistosome was found in two sites. The logistic regression analysis using remotely-sensed environmental data showed that NDVI was the significant variable influencing I. exutus distribution (B = -8.460, Sig = 0.043). Geospatial distribution maps were created to show the distribution of each snail species and potential transmission sites. This study mapped the distribution of snail hosts, identified possible transmission sites and demonstrates the presence of snail hosts of certain parasites in Abeokuta area (Abeokuta South and Abeokuta North Local Government Areas), the distribution of these snail hosts should be monitored to prevent transmission of these pathogens to humans.Keywords: geospatial, vector snails, trematode, distribution, malacological

Zoonotic tissue parasites of Australian wildlife

Increasing use of bushlands for recreational, commercial and scientific activities fosters movement across the urban-bushland interface. This may facilitate the transmission of parasitic diseases from wildlife to humans (zoonoses). The fashionable trend to consumption of game meats such as feral pig and crocodile, and raw fish such as sushi, sashimi and pickled herring has exacerbated the zoonotic potential of parasites of wildlife.

The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part II: Helminths and arthropods

Over the last few decades, ecological factors, combined with everchanging landscapes mainly linked to human activities (e.g. encroachment and tourism) have contributed to modifications in the transmission of parasitic diseases from domestic to wildlife carnivores and vice versa. In the first of this two-part review article, we have provided an account of diseases caused by protozoan parasites characterised by a two-way transmission route between domestic and wild carnivore species. In this second and final part, we focus our attention on parasitic diseases caused by helminth and arthropod parasites shared between domestic and wild canids and felids in Europe. While a complete understanding of the biology, ecology and epidemiology of these parasites is particularly challenging to achieve, especially given the complexity of the environments in which these diseases perpetuate, advancements in current knowledge of transmission routes is crucial to provide policy-makers with clear indications on strategies to reduce the impact of these diseases on changing ecosystems.

Parasites of cattle egrets (Bubulcus ibis) and the associated haematological and biochemical changes

Parasitic diseases play an important role for wild animals and it is recognised as a significant factor in the successful conservation of endangered species. Diagnosing parasite infection and load in free-ranging populations traditionally is done via necropsy or coproscopy. Forty cattle egrets ( Bubulcus ibis ) were captured and used for this study. The birds were examined for parasites and associated ectoparasites were collected and identified. Gastrointestinal content of each bird was also examine for adult and eggs of different helminthes and protozoan cysts while blood smears were examined microscopically to identify the different haemoprotozoa associated with the birds. The haematological parameters and serum biochemistry profile of these birds were also evaluated. Menopon gallinae was the only ectoparasite seen with a prevalence of 52.5%. The endoparasites observed include Ascaridia galli with the highest prevalence 14 (35%), Heterakis spp 7(17.5%), Trichostrongylus tenuis and Capillaria spp having the same prevalence 5(12.5%), Fascioloides magna 4(10%) and Syngamus trachea with 3(7.5%) had the lowest prevalence. Haemoproteus spp 9(22.5%) was the most prevalent haemoparasites observed with Leucocytozoon spp having a prevalence of 4(10%) while Plasmodium spp had the least prevalence of 3(7.5%). Eighty percent of the cattle egrets had at least one of the different endoparasites while 52.5% had ectoparasites and 40% had haemoparasites. There was a 22.5% prevalence of the combined co-infection of at least one each of the different endoparasites, ectoparasites and haemoparasites species in the cattle egrets. The risk of a co-infection of only endoparasites was found to be 20% while the infection with only ectoparasites and haemoparasite was found to be 2.5% in both cases. However, 92.5% of the cattle egrets had at least one of the different parasites while a combined infection of both Ectoparasite and endoparasite had the highest co-infection prevalence (25%). The study also showed that there was a significantly higher risk of co-infection of the different types of parasites in cattle egrets. There were significant differences in the haematological parameters and the serum biochemistry profile of the infected cattle egrets compared to the uninfected birds. This study suggests that cattle egret when living near poultry pen could serve as a reservoir host for the transmission of parasitic diseases. Further research on parasite host interaction of wildlife birds is warranted to determine their possible role in the biological transmission of diseases. Keyword: Wildlife, Cattle egrets, parasites, haematological parameters, serum biochemistry

Endoparasites in cattle nearby tribal areas of free-ranging protected areas of Tamil Nadu state.

Fresh dung samples from cattle nearby and tribal areas of free-ranging regions, Mudumalai Tiger Reserve, Anamalai Tiger Reserve and forest divisions of Sathyamangalam-Erode of Tamil Nadu state were examined for identification of endoparasitic infection. A total of 50 dung samples were collected and examination of samples revealed the presence of eggs of Strongyle, Strongyloides sp., amphistomes, Toxocara sp. and oocysts of Eimeria sp. The risk of parasitic disease transmission from domestic livestock to wild populations was discussed.

Central limit approximations for Markov population processes with countably many types

When modelling metapopulation dynamics, the influence of a single patch on the metapopulation depends on the number of individuals in the patch. Since there is usually no obvious natural upper limit on the number of individuals in a patch, this leads to systems in which there are countably infinitely many possible types of entity. Analogous considerations apply in the transmission of parasitic diseases. In this paper, we prove central limit theorems for quite general systems of this kind, together with bounds on the rate of convergence in an appropriately chosen weighted $\ell_1$ norm.

A law of large numbers approximation for Markov population processes with countably many types

When modelling metapopulation dynamics, the influence of a single patch on the metapopulation depends on the number of individuals in the patch. Since the population size has no natural upper limit, this leads to systems in which there are countably infinitely many possible types of individual. Analogous considerations apply in the transmission of parasitic diseases. In this paper, we prove a law of large numbers for quite general systems of this kind, together with a rather sharp bound on the rate of convergence in an appropriately chosen weighted ℓ 1 norm.

Prevalence of Myxobolus cerebralis Infections Among Genetic Lineages of Tubifex tubifex at Three Locations in the Madison River, Montana

Host biodiversity can impact disease risk and influence the transmission of parasitic disease. Stream sediment-dwelling worms, Tubifex tubifex (Clitellata: Oligochaeta), are the definitive host of the parasite Myxobolus cerebralis (Myxozoa: Myxosporea), which causes whirling disease in salmonid fishes. Genetic diversity of T. tubifex is correlated with host susceptibility to M. cerebralis , and mitochondrial Lineage III is generally shown to be more likely to be infected and produce the triactinomyxon (TAM) spores than other lineages. We determined the mitochondrial lineage, relative abundance, and prevalence of infection of T. tubifex collected at 3 sites in the Madison River, Montana, where previous study had shown variation in whirling disease prevalence and severity in caged trout fry. We also compared visual identification of TAMs released from cultured worms with a molecular genetic assay (diagnostic polymerase chain reaction [PCR]) for parasite detection of both infected and uninfected worms. We estimated that mitochondrial Lineage III was most abundant at the site previously shown to have high fish disease and was also most likely to be infected. The 2 techniques for detecting parasite infection did not always agree, and the likelihood of PCR (+) and spore (-) was not significantly different from PCR (-) and spore (+). Differences in the relative infection prevalence for these 2 lineages may explain the wide range of infection in natural streams.

Consequent Effects of Parasitism on Population Dynamics, Food Webs, and Human Health Under Climate Change

Consequent Effects of Parasitism on Population Dynamics, Food Webs, and Human Health Under Climate Change

Current situation of Cryptosporidium and other enteroparasites among patients with gastroenteritis from western cities of Mazandaran province, Iran, during 2007-2008

Aim : The aim of this study was to evaluate the prevalence rate of Cryptosporidium and other enteropathogen parasites among patients with gastroenteritis in western cities of Mazandaran province, northern Iran, during one year. Background : As specific characterization, high humidity, ecological conditions, superficial water sources, municipal water supplies, domestic and industrial animal husbandry and the rate of raining made Mazandaran as a favorable province for transmission of parasitic diseases. Patients and methods : This investigation was conducted between June 2007 to June 2008 in western cities of Mazandaran province, Northern Iran. Overall, 420 stool samples of gastroenteritis patients were collected from Chalous (194 sample), Tonekabon (187 sample) and Ramsar (39 sample), fixed and examined by Direct Method (DM) for diagnosis of enteropathogen parasites, Acid-Fast Staining (AFS) and Auramin Phenol Fluorescence (APF) for detection of Cryptosporidium and other sporozoan protozoa. Results : The results confirmed the overall prevalence rate of parasitic infections to be 2.14% (9 patients) among those cities, and the highest rate of infection was observed to be among Giardia lamblia (1.19%, 5 patients), Blastocystis hominis (0.71%, 3 patients) and Entamoeba coli (0.24%, 1 patient) respectively. There was no Cryptospordium and other sporozoan infection among the test samples. Comparative prevalence rates of parasitic infections in Chalous, Tonekabon and Ramsar were 1.55% (3 patients), 2.14% (4 patients) and 2.56% (1 patient) respectively. The relative frequencies of parasitic infections among infected individuals were associated with seasons, therefore the highest and the lowest rates were observed in autumn (40%) and spring (10%), respectively. Conclusion : Although, the current results showed a decline in the rate of parasitic infections in Mazandaran province recently in comparison with the past previous studies, the situation is always under caution for emerging and re-emerging enteropathogen parasites with the emphasize on opportunistic parasites.

Criticality of Parasitic Disease Transmission in a Diffusive Population

Through using the methods of finite-size effect and short time dynamic scaling, we study the critical behavior of parasitic disease spreading process in a diffusive population mediated by a static vector environment. Through comprehensive analysis of parasitic disease spreading we find that this model presents a dynamical phase transition from disease-free state to endemic state with a finite population density. We determine the critical population density, above which the system reaches an epidemic spreading stationary state. We also perform a scaling analysis to determine the order parameter and critical relaxation exponents. The results show that the model does not belong to the usual directed percolation universality class and is compatible with the class of directed percolation with diffusive and conserved fields.

Connectivity sustains disease transmission in environments with low potential for endemicity: modelling schistosomiasis with hydrologic and social connectivities

Social interaction and physical interconnections between populations can influence the spread of parasites. The role that these pathways play in sustaining the transmission of parasitic diseases is unclear, although increasingly realistic metapopulation models are being used to study how diseases persist in connected environments. We use a mathematical model of schistosomiasis transmission for a distributed set of heterogeneous villages to show that the transport of parasites via social (host movement) and environmental (parasite larvae movement) pathways has consequences for parasite control, spread and persistence. We find that transmission can be sustained regionally throughout a group of connected villages even when individual village conditions appear not to support endemicity. Optimum transmission is determined by an interplay between different transport pathways, and not necessarily by those that are the most dispersive (e.g. disperse social contacts may not be optimal for transmission). We show that the traditional targeting of villages with high infection, without regard to village interconnections, may not lead to optimum control. These findings have major implications for effective disease control, which needs to go beyond considering local variations in disease intensity, to also consider the degree to which populations are interconnected.

Global diversity of black flies (Diptera: Simuliidae) in freshwater

Black flies are a worldwide family of nematocerous Diptera whose immature stages are confined to running waters. They are key organisms in both aquatic and terrestrial ecosystems, but are perhaps best known for the bloodsucking habits of adult females. Attacks by black flies are responsible for reduced tourism, deaths in wild and domestic birds and mammals, and transmission of parasitic diseases to hosts, including humans. About 2,000 nominal species are currently recognized; however, certain geographical regions remain inadequately surveyed. Furthermore, studies of the giant polytene chromosomes of larvae reveal that many morphologically recognized species actually consist of two or more structurally indistinguishable (yet reproductively isolated) sibling species. Calculations derived from the best-known regional fauna—the Nearctic Region—reveal that the actual number of World black fly species exceeds 3,000.

Contaminación de los Parques Públicos de la Localidad de Suba, Bogotá con Nemátodos Zoonóticos

Establishing the presence of zoonotic gastrointestinal nematodosin soil samples in recreational areas in Suba (one of the largest localities of Bogotá, Colombia) between July 2005 and June 2006. The presence of several gastrointestinal parasites' eggs, larvae and oocysts were determined by initial soil sedimentation and later flotation with Sheather solution; some of them were responsible for important zoonotic diseases affecting the human population. Parasites were identified in 376 samples: Ancylostoma larvae (10.7%), Ancylostoma eggs (0.6%), Toxocara eggs (5.8%), Strongyloides eggs (3.3%), Dipylidium eggs (0.06%) and Sarcocystis oocysts (0.06%). Other parasites identified were Toxascaris eggs (0.9%), Spirocerca eggs (0.25%) and Isospora oocysts (0.25%). Some larvae and eggs present in 522 samples could not be classified and there was no evidence of parasites in 702 samples (45%). 94.2%, (n=49) of the recreational area was thus polluted. The high percentage of recreational areas so polluted indicated that these places would constitute a risk factor for the transmission of parasitic diseases to animals and human beings. Due to this sanitary problem's relevance in public health programmes, government policy must be determined involving communities so that people are educated to improve their sanitary practices in recreational places regarding caring for their pets.