Parasite counts or parasite incidences? Testing differences with four analyses of infracommunity modelling for seven parasite-host associations.

One of the challenges in studies of parasite community ecology is whether the input data for analyses should be parasite abundances/counts, i.e. count data (CD), or parasite incidences (presences/absences), i.e. incidence data (ID). We analysed species responses to environmental factors and species associations in the infracommunities of helminths and ectoparasites in four hosts from Europe (Sorex araneus and Myodes glareolus) and South Africa (Rhabdomys pumilio and Rhabdomys dilectus) and compared the results of four analyses [redundancy analysis (RD), RLQ analysis, joint species distribution modelling (JSDM) and Markov random fields (MRF)] that used either CD or ID as an input. In addition, we compared the differences between the CD and ID results of two analyses (JSDM and MRF) across parasite species between (a) host species within helminths and ectoparasites; (b) helminths and ectoparasites within a host species; and (c) parasite species with contrasting levels of intensity. The results of most analyses for the majority of parasite-host associations were qualitatively similar. However, models based on the ID input performed better than models based on the CD input in three out of four types of analyses (RDA, JSDM and MRF). The differences between the CD and ID models varied between host species (being the lowest in R. pumilio for JSDM and in S. araneus for MRF). However, they were not affected by the level of parasite intensity.

An assessment of potential biomarkers of environment enteropathy and its association with age and microbial infections among children in Bangladesh.

Interventional studies targeting environment enteropathy (EE) are impeded by the lack of appropriate, validated, non-invasive biomarkers of EE. Thus, we aimed to validate the association of potential biomarkers for EE with enteric infections and nutritional status in a longitudinal birth cohort study. We measured endotoxin core antibody (EndoCab) and soluble CD14 (sCD14) in serum, and myeloperoxidase (MPO) in feces using commercially available enzyme-linked immunosorbent assay (ELISA) kits. We found that levels of serum EndoCab and sCD14 increase with the cumulative incidence of enteric infections. We observed a significant correlation between the fecal MPO level in the children at 24 months of age with the total number of bacterial and viral infections, the total number of parasitic infections, and the total number of diarrheal episodes and diarrheal duration. We observed that the levels of serum EndoCab, sCD14, and fecal MPO at 3 months of age were significantly associated with whether children were malnourished at 18 months of age or not. Biomarkers such as fecal MPO, serum EndoCab and sCD14 in children at an early age may be useful as a measure of cumulative burden of preceding enteric infections, which are predictive of subsequent malnutrition status and may be useful non-invasive biomarkers for EE.

Priorities in research on foodborne parasites indicated by short-term scientific missions as part of COST Action a European Network for Foodborne Parasites (Euro-FBP).

The European Cooperation in Science and Technology (COST) is a funding organization for the creation of research networks. These networks support collaboration and networking among scientists across Europe and thereby give impetus to research advancements and innovation. One of the most important mechanisms of COST actions are the short-term scientific missions (STSM), which are a funding mechanism that enables scientists, particularly those earlier in their careers, to visit an institution or laboratory in another COST Member state in order to learn techniques that will enhance their skills and improve the scientific knowledge of their institution. The European Network for Foodborne Parasites (Euro-FBP; FA1408) was a COST Action that ended in early 2019, which brought together different experts with knowledge and interest on a broad spectrum of different foodborne parasites of relevance in Europe. In the course of the Euro-FBP COST Action, 32 such STSM occurred. This article provides a short overview of the short-term scientific missions that were approved during this action, as well as the relation of these actions to several relevant socio-economic parameters. The subjects of these STSM, the majority of which were concerned with detection techniques, probably reflect the priorities for research skills on foodborne parasites in Europe.

Parasitology should not be abandoned: data from outpatient parasitological testing in Guangdong, China.

Over the past six decades, the Chinese government made parasitoses with a high disease burden, including soil-transmitted nematode infections, malaria, leishmaniasis, filariasis, and schistosomiasis, a public health priority because they were seen to be crucial impediments to the development of rural areas. As a result, these debilitating parasitic diseases that used to be widely prevalent have been well controlled or eliminated. Consequently, less attention has been paid to parasitic infection during the rapid development of the economy, especially in developed areas. However, our investigations conducted in the parasitological laboratory of Sun Yat-sen University (Guangzhou, Guangdong, China) show that emerging parasitic diseases still threaten many people's health, with 340 of 880 outpatients (38.6%) receiving a diagnosis of parasitic disease, among whom 201 (59.1%) had clonorchiasis and 120 (35.3%) had taeniasis/cysticercosis. Furthermore, our doctors are not equipped with sufficient parasitology knowledge because this discipline is not able to maintain attraction. Many parasitic infections that result in severe consequences are treatable and preventable, but the phenomena of misdiagnosis and missed diagnosis are common and merit attention.

Zoonotic Parasites of Sheltered and Stray Dogs in the Era of the Global Economic and Political Crisis.

Sheltered and stray dogs, exposed to zoonotic parasites, including protozoa, helminths, and arthropods, may represent a major threat to public health. Resources for addressing health problems in these animals are not on the priority list of veterinary and public health authorities. Thus, dogs continue to represent an important reservoir for zoonotic parasites. In this article, we review the importance of sheltered and stray dogs as reservoirs of zoonotic parasites in different parts of the world, especially in the context of the current global political and economic crisis.

Potential Relevance of Melatonin Against Some Infectious Agents: A Review and Assessment of Recent Research.

Melatonin, a tryptophan-derived neurohormone found in animals, plants, and microbes, participates in various biological and physiological functions. Among other properties, numerous in vitro or in vivo studies have reported its therapeutic potential against many parasites, bacteria and viruses. In this concern, melatonin was found to be effective against many parasites such as Plasmodium, Toxoplasma gondii, and Trypansoma cruzi, via various mechanisms such as modulation of calcium level and/or host immune system. Likewise, a recent investigation has reported in vitro activity of melatonin against Leishmania infantum promastigotes which is the causative agent of fascinating visceral Leishmaniasis. This review was initially undertaken to summarize some facts about certain physiological and therapeutic effects of melatonin. It also reviews the effects and action mechanisms of melatonin in bacterial and viral infection besides biology of different parasites which may provide a promising strategy for control of many diseases of public health importance.

Genome mining offers a new starting point for parasitology research.

Parasites including helminthes, protozoa, and medical arthropod vectors are a major cause of global infectious diseases, affecting one-sixth of the world's population, which are responsible for enormous levels of morbidity and mortality important and remain impediments to economic development especially in tropical countries. Prevalent drug resistance, lack of highly effective and practical vaccines, as well as specific and sensitive diagnostic markers are proving to be challenging problems in parasitic disease control in most parts of the world. The impressive progress recently made in genome-wide analysis of parasites of medical importance, including trematodes of Clonorchis sinensis, Opisthorchis viverrini, Schistosoma haematobium, S. japonicum, and S. mansoni; nematodes of Brugia malayi, Loa loa, Necator americanus, Trichinella spiralis, and Trichuris suis; cestodes of Echinococcus granulosus, E. multilocularis, and Taenia solium; protozoa of Babesia bovis, B. microti, Cryptosporidium hominis, Eimeria falciformis, E. histolytica, Giardia intestinalis, Leishmania braziliensis, L. donovani, L. major, Plasmodium falciparum, P. vivax, Trichomonas vaginalis, Trypanosoma brucei and T. cruzi; and medical arthropod vectors of Aedes aegypti, Anopheles darlingi, A. sinensis, and Culex quinquefasciatus, have been systematically covered in this review for a comprehensive understanding of the genetic information contained in nuclear, mitochondrial, kinetoplast, plastid, or endosymbiotic bacterial genomes of parasites, further valuable insight into parasite-host interactions and development of promising novel drug and vaccine candidates and preferable diagnostic tools, thereby underpinning the prevention and control of parasitic diseases.

Neglected tropical diseases in Central America and Panama: review of their prevalence, populations at risk and impact on regional development.

A review of the literature since 2009 reveals a staggering health and economic burden resulting from neglected tropical diseases in Panama and the six countries of Central America (referred to collectively here as 'Central America'). Particularly at risk are the 10.2million people in the region who live on less than $2 per day, mostly in Guatemala, Honduras, Nicaragua and El Salvador. Indigenous populations are especially vulnerable to neglected tropical diseases. Currently, more than 8million Central American children require mass drug treatments annually (or more frequently) for their intestinal helminth infections, while vector-borne diseases are widespread. Among the vector-borne parasitic infections, almost 40% of the population is at risk for malaria (mostly Plasmodium vivax infection), more than 800,000 people live with Chagas disease, and up to 39,000 people have cutaneous leishmaniasis. In contrast, an important recent success story is the elimination of onchocerciasis from Central America. Dengue is the leading arbovirus infection with 4-5million people affected annually and hantavirus is an important rodent-borne viral neglected tropical disease. The leading bacterial neglected tropical diseases include leptospirosis and trachoma, for which there are no disease burden estimates. Overall there is an extreme dearth of epidemiological data on neglected tropical diseases based on active surveillance as well as estimates of their economic impact. Limited information to date, however, suggests that neglected tropical diseases are a major hindrance to the region's economic development, in both the most impoverished Central American countries listed above, as well as for Panama and Costa Rica where a substantial (but largely hidden) minority of people live in extreme poverty.

Molecular diagnosis in clinical parasitology: when and why?

Microscopic detection and morphological identification of parasites from clinical specimens are the gold standards for the laboratory diagnosis of parasitic infections. The limitations of such diagnostic assays include insufficient sensitivity and operator dependence. Immunoassays for parasitic antigens are not available for most parasitic infections and have not significantly improved the sensitivity of laboratory detection. Advances in molecular detection by nucleic acid amplification may improve the detection in asymptomatic infections with low parasitic burden. Rapidly accumulating genomic data on parasites allow the design of polymerase chain reaction (PCR) primers directed towards multi-copy gene targets, such as the ribosomal and mitochondrial genes, which further improve the sensitivity. Parasitic cell or its free circulating parasitic DNA can be shed from parasites into blood and excreta which may allow its detection without the whole parasite being present within the portion of clinical sample used for DNA extraction. Multiplex nucleic acid amplification technology allows the simultaneous detection of many parasitic species within a single clinical specimen. In addition to improved sensitivity, nucleic acid amplification with sequencing can help to differentiate different parasitic species at different stages with similar morphology, detect and speciate parasites from fixed histopathological sections and identify anti-parasitic drug resistance. The use of consensus primer and PCR sequencing may even help to identify novel parasitic species. The key limitation of molecular detection is the technological expertise and expense which are usually lacking in the field setting at highly endemic areas. However, such tests can be useful for screening important parasitic infections in asymptomatic patients, donors or recipients coming from endemic areas in the settings of transfusion service or tertiary institutions with transplantation service. Such tests can also be used for monitoring these recipients or highly immunosuppressed patients, so that early preemptive treatment can be given for reactivated parasitic infections while the parasitic burden is still low.

[Assessment of the quality of laboratory diagnosis of intestinal parasitic diseases by the laboratories participating in the Federal System of External Quality Assessment of Clinical Laboratory Testing].

In 2010-2013, the quality of microscopic detection of the causative agents ofparasitic diseases in the feces has been assessed by the specialists of the laboratories of the therapeutic-and-prophylactic institutions (TPIs) and Hygiene and Epidemiology Centers, Russian Inspectorate for the Protection of Consumer Rights and Human Welfare, which are participants of the Federal System of External Quality Assessment of Clinical Laboratory Testing. Thirty-two specimens containing 16 species of human helminths and 4 species of enteric protozoa in different combinations were examined. The findings suggest that the quality of microscopic detection of the causative agents of parasitic diseases is low in the laboratories of health care facilities and that the specialists of the laboratories of TPIs and Hygiene and Epidemiology Centers, Russian Inspectorate for the Protection of Consumer Rights and Human Welfare, do not not possess the knowledge and skills necessary to make a laboratory diagnosis of helminths and enteric protozoa. The average detection rates of helminths and protozoa were at a level of 64 and 36%, respectively. The correct results showed that the proportion of helminths and protozoa were 94.5 and 5.5%, respectively. According to the biological and epidemiological classification of helminths, there were higher detection rates for contact group parasites (Enterobius vermicularis and Hymenolepis nana) and geohelminths (Ascaris, Trichuris trichiura, and others). Biohelminths (Opisthorchis, tapeworms, and others) Were detectable slightly worse.

Modeling parasite infection dynamics when there is heterogeneity and imperfect detectability.

Understanding the infection and recovery rate from parasitic infections is valuable for public health planning. Two challenges in modeling these rates are (1) infection status is only observed at discrete times even though infection and recovery take place in continuous time and (2) detectability of infection is imperfect. We address these issues through a Bayesian hierarchical model based on a random effects Weibull distribution. The model incorporates heterogeneity of the infection and recovery rate among individuals and allows for imperfect detectability. We estimate the model by a Markov chain Monte Carlo algorithm with data augmentation. We present simulation studies and an application to an infection study about the parasite Giardia lamblia among children in Kenya.

One world health: socioeconomic burden and parasitic disease control priorities.

Parasitic diseases present a considerable socio-economic impact to society. Zoonotic parasites can result in a considerable burden of disease in people and substantive economic losses to livestock populations. Ameliorating the effects of these diseases may consist of attempts at eradicating specific diseases at a global level, eliminating them at a national or local level or controlling them to minimise incidence. Alternatively with some parasitic zoonoses it may only be possible to treat human and animal cases as they arise. The choice of approach will be determined by the potential effectiveness of a disease control programme, its cost and the cost effectiveness or cost benefit of undertaking the intervention. Furthermore human disease burden is being increasingly measured by egalitarian non-financial measures which are difficult to apply to livestock. This adds additional challenges to the assessment of socio-economic burdens of zoonotic diseases. Using examples from the group of neglected zoonotic diseases, information regarding the socio-economic effects is reviewed together with how this information is used in decision making with regard to disease control and treatment.

[Analysis report of the national technique competition for diagnosis of parasitic diseases in 2012: I. Capability analysis of Plasmodium detection].

OBJECTIVE: To analyze the result of the national technique competition for diagnosis of parasitic diseases in 2012, so as to understand the capability of detection on Plasmodium parasites among professionals from institutes for disease control and prevention at different levels. METHODS: Four professionals from institution were selected as contestants (age < or = 45 and at least two contestants from county-level institution). The content of the competition included making thick and thin blood slides of Plasmodium (3 slides in 30 min, 10 scores as full marks and 6 as passing score) and identification of species and number with microscopy (5 slides, 8 min per slide, 30 scores as full marks and 18 as passing score). All contestants were grouped by gender, age, professional title, level of institution, classification according to malaria endemicity, geographical location and economic development of the province. Their scores were statistically analyzed by SPSS 16.0 software. RESULTS: The average score of blood smear making test in 120 contestants from 30 provinces was 8.7, the highest was 10 and the lowest was 5.8, 118 (98.3%) contestants passed the test. The average score of blood smear reading was 16.0, the highest was 29 and the lowest was 0, 52 (43.3%) contestants passed the test. There were no significant differences for the scores among genders, ages (< or = 30, 31-40, > 40), professional titles (junior, intermediate and senior), institution levels (provincial, municipal or county level) (P > 0.05). However, there was a significant difference among provinces with different malaria endemicity, geographical location and development status (P < 0.05). For the blood slide-making and film-reading, scores of contestants from malaria endemic provinces including Class I (9.29 +/- 0.41, 18.17 +/- 6.42), Class II (8.92 +/- 0.79, 18.31 +/- 6.94) and Class III (8.61 +/- 0.89, 15.63 +/- 7.52) were higher than those from non-endemic provinces (7.95 +/- 1.00, 10.19 +/- 7.01) (P < 0.01). Scores of contestants from southern provinces (9.16 +/- 0.61, 18.82 +/- 6.78) were significantly higher than that from northern ones (8.30 +/- 0.99, 13.23 +/- 7.45) (P < 0.01). The film-reading scores were significantly higher in those from eastern provinces (18.20 +/- 6.88) than those from western (13.39 +/- 7.60) (P < 0.05), while no significant difference was found in blood slide-making (P > 0.05). CONCLUSION: The capability of malaria parasite detection is imbalanced.

Ocorrência de enteroparasitoses na população de um bairro da cidade de Cândido Mota-SP / Occurrence of enteroparasitoses in the population of a neighbourhood in the city of Cândido Mota-SP

Objetivo - Verificar a incidência de parasitoses intestinais na população de um bairro da cidade de Cândido Mota-SP, e verificar a possibilidade de associação entre a ocorrência de parasitoses e as condições socioeconômicas e sanitárias. As parasitoses intestinais são consideradas um problema de saúde pública, principalmente onde as condições de saneamento básico, higiene pessoal e o nível intelectual do indivíduo são precários, o que pode facilitar a transmissão. Métodos - As coletas foram feitas nas residências e as fezes analisadas pelos métodos de Hoffmann et al. e Faust et al., enquanto que o nível socioeconômico foi investigado através de questionário, respondido pelo responsável pela residência. Resultados - Foram analisadas 177 amostras e 35% encontrados: Ascaris lumbricoides, Giardia lamblia, Entamoeba histolytica, Enterobius vermicularis, Strongyloides stercoralis, Trichuris trichiura, com um caso de biparasitismos (Entamoeba coli com Ancylostomidae) e a faixa etária mais jovem foi a mais acometida. Da população estudada, 69% afirmaram não ter nenhum ou muito pouco conhecimento sobre as enteroparasitoses. Conclusão - A grande maioria da população residente no bairro era de baixa renda, com famílias numerosas vivendo em casas pequenas, demonstrando precariedade de higiene pessoal, ambiental e habitacional e o baixo conhecimento sobre as enteroparasitoses. Assim, é de suma importância a conscientização das populações quanto às principais formas de transmissão e profilaxia das enteroparasitoses, visando diminuir os índices apresentados, dando ênfase a trabalhos nas escolas que estimulem os hábitos de higiene pessoal e do ambiente.

Objective - To verify the incidence of intestinal parasitoses in the population of a neighbourhood in the city of Cândido Mota-SP, and the possibility of association between parasitosis conditions and sanitation and socioeconomic conditions. Intestinal parasitoses are considered a public health problem, especially in areas where basic sanitation conditions, personal hygiene and educational level of the individual are precarious, which may favour transmission. Methods - The collections were made in residences and the faeces were analysed through Hoffmann et al. and Faust et al. methods, and the socioeconomic level was investigated through questionnaires, answered by the person responsible for the household. Results - A total of 177 samples were analysed and 35% of them were positive for one or more types of parasites,and the most commonly found were: Ascaris lumbricoides, Giardia lamblia, Entamoeba histolytica, Enterobius vermicularis, Strongyloides stercoralis, Trichuris trichiura, with one case of biparasitism (Entamoeba coli with Ancylostomidae) and the youngest age range was the most affected. Of the studied population 69% claimed not to have or have very little knowledge of enteroparasitoses. Conclusion - Most of the population living in that neighbourhood consisted of low-income, large families living in small houses, showing precarious personal, environmental and residential hygiene, and little knowledge of enteroparasitoses. Therefore, it is essential to create awareness regarding the mainforms of transmission and prophylaxis of enteroparasitoses, aiming to reduce the present rates, emphasizing school work whicher stimulates environmental and personal hygiene habits.

The socioeconomic burden of parasitic zoonoses: global trends.

Diseases resulting from zoonotic transmission of parasites are common. Humans become infected through food, water, soil and close contact with animals. Most parasitic zoonoses are neglected diseases despite causing a considerable global burden of ill health in humans and having a substantial financial burden on livestock industries. This review aims to bring together the current data available on global burden estimates of parasitic zoonoses and indicate any changes in the trends of these diseases. There is a clear need of such information as interventions to control zoonoses are often in their animal hosts. The costs of such interventions together with animal health issues will drive the cost effectiveness of intervention strategies. What is apparent is that collectively, parasitic zoonoses probably have a similar human disease burden to any one of the big three human infectious diseases: malaria, tuberculosis or HIV in addition to animal health burden. Although the global burden for most parasitic zoonoses is not yet known, the major contributors to the global burden of parasitic zoonoses are toxoplasmosis, food borne trematode infections, cysticercosis, echinococcosis, leishmaniosis and zoonotic schistosomosis. In addition, diarrhoea resulting from zoonotic protozoa may have a significant impact.

Bacteriological and parasitological assessment of food handlers in the Omdurman area of Sudan.

BACKGROUND/PURPOSE: Pathogenic organisms are thought to be widely distributed among food handlers. This study was designed to assess the prevalence of carriers of some pathogenic bacteria and intestinal parasites among food handlers in the city of Omdurman, Sudan. METHODS: A total of 518 nasal swabs and stool specimens were collected. Nasal swabs were cultured on bacteriological culture media. Stool specimens were examined microscopically for intestinal parasites. RESULTS: Of the total subjects examined, 30.1% were found to be carriers of pathogenic organisms. The pathogens isolated and identified were the bacteria Staphylococcus aureus, Salmonella typhi, and Shigella boydii, and the intestinal parasites, Giardia lamblia and Entamoeba histolytica/dispar. Bacteria and intestinal parasites were most prevalent among storekeepers (41%), followed by restaurant workers (24.4%), bakers (24.4%), butchers (5.1%), milk distributors (2.6%), and fruits/vegetables sellers (2.6%). S. aureus, the most abundant pathogen, was most prevalent in storekeepers (44.6%), followed by restaurant workers (25%), bakers (17.9%), butchers (5.4%), milk distributors (3.6%), and fruit/vegetable sellers (3.6%). CONCLUSION: The findings from this study indicate a key role for food handlers in the spread and transmission of food communicable diseases and reveal the need for protective measures.

The health impact of polyparasitism in humans: are we under-estimating the burden of parasitic diseases?

Parasitic infections are widespread throughout the tropics and sub-tropics, and infection with multiple parasite species is the norm rather than the exception. Despite the ubiquity of polyparasitism, its public health significance has been inadequately studied. Here we review available studies investigating the nutritional and pathological consequences of multiple infections with Plasmodium and helminth infection and, in doing so, encourage a reassessment of the disease burden caused by polyparasitism. The available evidence is conspicuously sparse but is suggestive that multiple human parasite species may have an additive and/or multiplicative impact on nutrition and organ pathology. Existing studies suffer from a number of methodological limitations and adequately designed studies are clearly necessary. Current methods of estimating the potential global morbidity due to parasitic diseases underestimate the health impact of polyparasitism, and possible reasons for this are presented. As international strategies to control multiple parasite species are rolled-out, there is a number of options to investigate the complexity of polyparasitism, and it is hoped that that the parasitological research community will grasp the opportunity to understand better the health of polyparasitism in humans.