Severity of bovine tuberculosis is associated with co-infection with common pathogens in wild boar

Social ageing can protect against infectious disease in a group-living primate

The benefits of social living are well established, but sociality also comes with costs, including infectious disease risk. This cost-benefit ratio of sociality is expected to change across individuals' lifespans, which may drive changes in social behaviour with age. To explore this idea, we combine data from a group-living primate for which social ageing has been described with epidemiological models to show that having lower social connectedness when older can protect against the costs of a hypothetical, directly transmitted endemic pathogen. Assuming no age differences in epidemiological characteristics (susceptibility to, severity and duration of infection), older individuals suffered lower infection costs, which was explained largely because they were less connected in their social networks than younger individuals. This benefit of 'social ageing' depended on epidemiological characteristics and was greatest when infection severity increased with age. When infection duration increased with age, social ageing was beneficial only when pathogen transmissibility was low. Older individuals benefited most from having a lower frequency of interactions (strength) and network embeddedness (closeness) and benefited less from having fewer social partners (degree). Our study provides a first examination of the epidemiology of social ageing, demonstrating the potential for pathogens to influence the evolutionary dynamics of social ageing in natural populations.This article is part of the discussion meeting issue 'Understanding age and society using natural populations'.

Social ageing can protect against infectious disease in a group-living primate

The benefits of social living are well established, but sociality also comes with costs, including infectious disease risk. This cost-benefit ratio of sociality is expected to change across individuals' lifespans, which may drive changes in social behaviour with age. To explore this idea, we combine data from a group-living primate for which social ageing has been described with epidemiological models to show that having lower social connectedness when older can protect against the costs of a hypothetical, directly transmitted endemic pathogen. Assuming no age differences in epidemiological characteristics (susceptibility to, severity, and duration of infection), older individuals suffered lower infection costs, which was explained largely because they were less connected in their social networks than younger individuals. This benefit of 'social ageing' depended on epidemiological characteristics and was greatest when infection severity increased with age. When infection duration increased with age, social ageing was beneficial only when pathogen transmissibility was low. Older individuals benefited most from having a lower frequency of interactions (strength) and network embeddedness (closeness) and benefited less from having fewer social partners (degree). Our study provides a first examination of the epidemiology of social ageing, demonstrating the potential for pathogens to influence evolutionary dynamics of social ageing in natural populations.

A systematic review and guide for using multi-response statistical models in co-infection research

The simultaneous infection of organisms with two or more co-occurring pathogens, otherwise known as co-infections, concomitant infections or multiple infections, plays a significant role in the dynamics and consequences of infectious diseases in both humans and animals. To understand co-infections, ecologists and epidemiologists rely on models capable of accommodating multiple response variables. However, given the diversity of available approaches, choosing a model that is suitable for drawing meaningful conclusions from observational data is not a straightforward task. To provide clearer guidance for statistical model use in co-infection research, we conducted a systematic review to (i) understand the breadth of study goals and host-pathogen systems being pursued with multi-response models and (ii) determine the degree of crossover of knowledge among disciplines. In total, we identified 69 peer-reviewed primary studies that jointly measured infection patterns with two or more pathogens of humans or animals in natural environments. We found stark divisions in research objectives and methods among different disciplines, suggesting that cross-disciplinary insights into co-infection patterns and processes for different human and animal contexts are currently limited. Citation network analysis also revealed limited knowledge exchange between ecology and epidemiology. These findings collectively highlight the need for greater interdisciplinary collaboration for improving disease management.

Occurrence and identification of lungworms in Iranian wild boars

This study represents the first investigation into the occurrence and identification of Metastrongylus spp. in wild boars (Sus scrofa) in Iran, utilizing both molecular and morphological methods. Thirteen wild boars from Kerman Province were examined, with 92.3% found to be infected with at least one species of Metastrongylus. Mixed infections were observed in 38.46% of the animals. Morphological and molecular analyses confirmed the presence of M. pudendotectus and M. salmi, with prevalence rates of 76.9% and 53.9%, respectively. Histopathological examination revealed transverse and longitudinal sections of Metastrongylus parasites within the airways, causing partial to complete obstruction, interstitial pneumonia, and inflammatory responses. The study also highlights the public health significance of these parasites. The higher prevalence observed compared to earlier studies suggests changes in environmental conditions, host dynamics, or agricultural practices as possible factors, warranting further investigation. The findings underscore the need for comprehensive surveillance and control measures to mitigate the risk of zoonotic transmission, particularly in regions with significant wild and domestic swine populations. This study contributes to the understanding of Metastrongylus spp. distribution and their pathological impact, emphasizing the ecological importance of wild boars and the necessity for continued monitoring and research to prevent and control infections in both animal and human populations.

Prevalence of Intestinal Parasitic Infections and Associated Factors among Presumptive Pulmonary Tuberculosis Patients at Debre Tabor Referral Hospital, South Gondar, Northwest Ethiopia: A Cross-Sectional Study

Background

In developing countries, intestinal parasitic infections (IPIs) and tuberculosis (TB) coinfections have been perceived to be high. The geographic distributions of helminths and TB overlap substantially. Parasitic infections affect the outcome of TB by changing the cell-mediated immune response to a humoral response, while Mycobacterium infection favors the immune escape of helminths. There are limited studies on the epidemiology of intestinal parasites among presumptive pulmonary TB (PTB) patients in Ethiopia. Therefore, this study is aimed at determining the prevalence of intestinal parasitic infections and associated factors among patients with presumptive pulmonary tuberculosis at Debre Tabor Referral Hospital.

Methods and Materials

A hospital-based cross-sectional study was conducted from March to June 2021. The sociodemographic data and associated factors were collected using a structured questionnaire, and stool samples were collected by convenient sampling technique and processed for the detection of intestinal parasites using a direct wet mount saline preparation and formal ether concentration technique. The data was coded, cleaned, and analyzed by SPSS version 23. Bivariate and multivariable analyses were conducted to determine an adjusted odds ratio (AOR). p value < 0.05 was considered statistically significant.

Result

The overall prevalence of intestinal parasitosis was 25.6% (81/316); of these, 12.9% (41/316) were protozoan infections and 12.7% (40/316) were helminth infections. Multivariable logistic regression analysis showed that being older than 36 years (AOR: 4.35; 95% CI: 1.26, 13.91; p = 0.001), rural residence (AOR: 3.46; 95% CI: 1.18, 9.97; p < 0.001), unable to read and write (AOR = 2.62; 95%CI = 2.15, 8.43; p = 0.004), and use of river water (AOR: 3.47; 95% CI: 1.62, 8.21; p < 0.001) were associated with intestinal parasitic infections.

Conclusion

The present study showed that the prevalence of intestinal parasitosis among presumptive pulmonary tuberculosis patients was high in the study area. Age, residence, educational status, and source of water were significant factors in IPIs among presumptive TB patients. Moreover, our findings suggest a proper health education program for good personal hygiene habits, the coloration of water, avoiding open-field defecation, and also preventative measures to avoid the acquisition of IPIs in patients with TB. Presumptive tuberculosis patients should be screened and treated accordingly. Additionally, it needs further research and recommends more assessment for intestinal parasitic infection in PTB patients.

Ranavirus and helminth parasite co-infection in invasive American bullfrogs in the Atlantic forest, Brazil

Emerging infectious diseases threaten amphibian species across the globe. In Brazil, the American bullfrog (Aquarana catesbeiana) is a highly invasive species that can potentially transmit parasites and pathogens to native amphibians. This is the first assessment of co-infection of Ranavirus and helminth macroparasites in invasive populations of bullfrogs in South America. We collected, measured, and euthanized 65 specimens of A. catesbeiana sampled from 9 sites across three states of Brazil in the Atlantic Forest biome. We collected and identified helminth macroparasites and sampled host liver tissue to test for the presence and load of Ranavirus with quantitative PCR. We documented patterns of prevalence, parasite load, and co-infection with generalized linear mixed models, generalized logistic regressions, and randomization tests. Most individual bullfrogs did not exhibit clinical signs of infection, but the overall Ranavirus prevalence was 27% (95% confidence interval, [CI 17-38]). Bullfrogs were infected with helminth macroparasites from 5 taxa. Co-infection of helminth macroparasites and Ranavirus was also common (21% CI [12-31]). Bullfrog size was positively correlated with total macroparasite abundance and richness, and the best-fitting model included a significant interaction between bullfrog size and Ranavirus infection status. We observed a negative correlation between Ranavirus viral load and nematode abundance (slope = -0.22, P = 0.03). Invasive bullfrogs (A. catesbeiana) in Brazil were frequently infected with both Ranavirus and helminth macroparasites, so adult bullfrogs could serve as reservoir hosts for both pathogens and parasites. However, many macroparasites collected were encysted and not developing. Coinfection patterns suggest a potential interaction between Ranavirus and macroparasites because helminth abundance increased with bullfrog size but was lower in Ranavirus infected individuals. Future studies of bullfrogs in the Atlantic Forest should investigate their potential role in pathogen and parasite transmission to native anurans.

Morphometric, histopathological and molecular findings of Macracanthorhynchus hirudinaceus infection in wild boar (Sus scrofa) from continental Italy

Although Macracanthorhynchus hirudinaceus is a neglected acanthocephalan of suids occasionally responsible for severe infections in humans, the spread of wild boar (Sus scrofa) populations in Europe could promote the circulation. Herein, we report the first morphometric, histological and molecular characterization of a severe M. hirudinaceus infection in a boar from continental Italy. The boar's intestine displayed granulomatous enteritis due to 24 helminths (14 females, 10 males), identified as adults of M. hirudinaceus by a combined morphometric/molecular approach. The phylogenetic analysis of the cox1 gene revealed a close relationship of the M. hirudinaceus sequence type found herein with those from Hungary and insular Italy. The high haplotype diversity and low nucleotide diversity of M. hirudinaceus specimens would suggest its rapid demographic expansion in the Mediterranean basin. More research is needed to assess the presence of M. hirudinaceus in susceptible beetle species and the role of boars in the epidemiology of infection.

Combination with Annual Deworming Treatments Does Not Enhance the Effects of PCV2 Vaccination on the Development of TB in Wild Boar Populations

Vaccination against PCV2 has been proven to be an effective measure to reduce the severity of TB in wild boar. The combination of this measure with strategies focused on treating other key concomitant pathogens, such as nematodes, could be a useful strategy. This study assesses whether a combination of deworming treatments and PCV2 vaccination may reduce the prevalence and severity of TB in wild boar. The study was conducted on five game estates in mid-western Spain where four groups of wild boar were produced: control, vaccinated, dewormed and vaccinated-dewormed. Wild boars from all groups were hunted between 2017 and 2020, and all of them received a TB diagnosis based on pathological and microbiological tests. Generalised linear models were used to explore the effect of deworming and PCV2 vaccination on TB prevalence and severity. PCV2-vaccinated animals showed lower probabilities of suffering severe TB lesions. However, no differences regarding TB severity were found between dewormed and non-dewormed wild boar. PCV2 vaccination reduces TB severity in wild boar. However, annual deworming does not produce a long-term parasitological reduction that can influence the development of TB in wild boar, nor does it improve the effect of PCV2 vaccination on TB.

A serological survey of pathogens associated with the respiratory and digestive system in the Polish European bison (Bison bonasus) population in 2017-2022

BACKGROUND

The European bison (Bison bonasus) is a near threatened species and requires health monitoring. The aim of the present study was to determine the prevalence of antibodies to pathogens known to cause respiratory and digestive illness in ruminants.

RESULTS

In the studied 328 European bison, the highest seroprevalence was observed for Bovine herpesvirus-1 (BoHV-1) (50.27%), Bovine Coronavirus (BCoV) (26.36%), and Bluetongue Virus (BTV) (12.83%). For Mycoplasma bovis strains and Bovine Viral Diarrhea Virus (BVDV), positive results were rare. Interestingly, a higher prevalence of BTV antibodies was noted in the northeastern populations and older animals.

CONCLUSIONS

Our findings indicate that the Polish European bison population appears to have considerable contact with BoHV-1; however, this does not appear to be of great significance, as clinical symptoms and post-mortem lesions are rarely noted in Polish European bison population. The high seroprevalence of BTV in the north-east of Poland is an ongoing trend, also noted in previous studies. It is possible that European bison may perpetuate the virus in this region. This is the first report of antibodies for BCoV in European bison.

Co-exposure to pathogens in wild ungulates from Doñana National Park, South Spain

Multiple infections or co-exposure to pathogens should be considered systematically in wildlife to better understand the ecology and evolution of host-pathogen relationships, so as to better determine the potential use of multiple pathogens as indicators to guide health management. We describe the pattern of co-exposure to several pathogens (i.e. simultaneous positive diagnosis to pathogens in an individual considering Mycobacterium tuberculosis complex lesions, and the presence of antibodies against Toxoplasma gondii, bluetongue virus, and hepatitis E virus) and assessed their main drivers in the wild ungulate community from Doñana National Park (red deer, fallow deer, and wild boar) for a 13-years longitudinal study. The lower-than-expected frequency of co-exposure registered in all species was consistent with non-mutually exclusive hypotheses (e.g. antagonism or disease-related mortality), which requires further investigation. The habitat generalist species (red deer and wild boar) were exposed to a greater diversity of pathogens (frequency of co-exposure around 50%) and/or risk factors than fallow deer (25.0% ± CI95% 4.9). Positive relationships between pathogens were evidenced, which may be explained by common risk factors favouring exposure. The specific combination of pathogens in individuals was mainly driven by different groups of factors (individual, environmental, stochastic, and populational), as well as its interaction, defining a complex eco-epidemiological landscape. To deepen into the main determinants and consequences of co-infections in a complex assemblage of wild hosts, and at the interface with humans and livestock, there also is needed to expand the range of pathogens and compare diverse assemblages of hosts under different environmental and management circumstances.

Tissue-specific assessment of oxidative status: Wild boar as a case study

In recent decades, there has been a fast-growing interest in using biomarkers of oxidative stress (BOS) in conservation programs of many vertebrate species. Biomarkers of oxidative stress can be measured in different biological samples (e.g., body fluids and tissues). However, since comparisons of the same battery of BOS among tissues of the same individual are scarce in the literature, the chosen target tissues regularly rely on arbitrary decisions. Our research aimed to determine if the oxidative status of free-ranging wild boar (Sus scrofa) naturally infected with Mycobacterium spp (etiological agent of tuberculosis, TB), varies depending on the sample where it was quantified. We compared antioxidant p-nitrophenyl esterase activity (EA), glutathione peroxidase (GPX) concentrations, and total oxidative status (TOS) in serum, lung, spleen, kidney, and muscle of 63 wild boar hunter-harvested in central Spain. Biomarkers of oxidative stress in serum had higher concentrations than in other tissues. The poor agreement between serum and other tissues highlights the importance of running complete BOS assessments in the same fluid or tissue. Further, low concentrations of BOS in tissues of TB-affected individuals were observed, and significant differences between healthy and sick boar were only detected in the serum of individuals developing mild TB and in the muscle of individuals with mild or severe disease status. However, all organs from wild boars affected with mild TB were not in oxidative imbalance compared to healthy control animals, suggesting that wild boars may cope well with TB. Our data indicate that serum and other tissues can be used as BOS in field conservation programs to monitor wildlife population health. Still, context-specific validations are needed to determine the most appropriate samples to use.

Two decades of tuberculosis surveillance reveal disease spread, high levels of exposure and mortality and marked variation in disease progression in wild meerkats

Infections with tuberculosis (TB)-causing agents of the Mycobacterium tuberculosis complex threaten human, livestock and wildlife health globally due to the high capacity to cross trans-species boundaries. Tuberculosis is a cryptic disease characterized by prolonged, sometimes lifelong subclinical infections, complicating disease monitoring. Consequently, our understanding of infection risk, disease progression, and mortality across species affected by TB remains limited. The TB agent Mycobacterium suricattae was first recorded in the late 1990s in a wild population of meerkats inhabiting the Kalahari in South Africa and has since spread considerably, becoming a common cause of meerkat mortality. This offers an opportunity to document the epidemiology of naturally spreading TB in a wild population. Here, we synthesize more than 25 years' worth of TB reporting and social interaction data across 3420 individuals to track disease spread, and quantify rates of TB social exposure, progression, and mortality. We found that most meerkats had been exposed to the pathogen within eight years of first detection in the study area, with exposure reaching up to 95% of the population. Approximately one quarter of exposed individuals progressed to clinical TB stages, followed by physical deterioration and death within a few months. Since emergence, 11.6% of deaths were attributed to TB, although the true toll of TB-related mortality is likely higher. Lastly, we observed marked variation in disease progression among individuals, suggesting inter-individual differences in both TB susceptibility and resistance. Our results highlight that TB prevalence and mortality could be higher than previously reported, particularly in species or populations with complex social group dynamics. Long-term studies, such as the present one, allow us to assess temporal variation in disease prevalence and progression and quantify exposure, which is rarely measured in wildlife. Long-term studies are highly valuable tools to explore disease emergence and ecology and study host-pathogen co-evolutionary dynamics in general, and its impact on social mammals.

Effects of parasites coinfection with other pathogens on animal host: A literature review

A parasite-host relationship is complicated and largely remained poorly understood, especially when mixed infections involving pathogenic bacteria and viruses are present in the same host. It has been found that most parasites are able to manipulate the host's immune responses to evade or overcome its defense systems. Several mechanisms have been postulated that may explain this phenomenon in different animal species. Recent evidence suggests that coinfections involving many parasitic species alter the host's vulnerability to other microorganisms, hinder diagnostic accuracy, and may negatively impact vaccination by altering the host's immune responsiveness. The objective of this review was to provide a comprehensive summary of the current understanding of how parasites interact with other pathogens in different animal species. A better understanding of this complex relationship will aid in the improvement efforts of disease diagnosis, treatment, and control measures such as novel and effective vaccines and therapeutics for infectious diseases.

Generalized tuberculosis due to Mycobacterium caprae in a red fox phylogenetically related to livestock breakdowns

Background

Tuberculosis (TB) due to Mycobacterium caprae is endemic in goat herds and free-ranging wild boars in Spain, causing infections in other livestock or wild animals to a lesser extent. TB infection in foxes is infrequently reported and they are usually considered spillover hosts of TB.

Case presentation

A blind, depressed and severely emaciated red fox (Vulpes vulpes) was admitted to a rehabilitation center. After clinical examination it was humanely sacrificed. At necropsy, generalized TB lesions were observed that were subsequently confirmed by histopathology along with a co-infection with canine distemper virus. M. caprae was isolated from mycobacterial culture and spoligotype SB0415 was identified. Whole genome sequencing (WGS) of the isolated M. caprae was carried out and single nucleotide polymorphisms (SNP) were compared with other sequences of M. caprae isolated from livestock and wildlife of the same area throughout the last decade.

Conclusions

This is the first reported case of TB due to M. caprae in a fox in the Iberian Peninsula. WGS and SNP analysis, together with spatial-temporal investigations, associated this case with recent M. caprae outbreaks in cattle and goat herds of the area. The results indicated transmission of M. caprae between livestock and the fox, suggesting that this species may occasionally play a role in the epidemiology of animal TB.

Long-Term Serological Investigations of Influenza A Virus in Free-Living Wild Boars (Sus scrofa) from Northern Italy (2007–2014)

Influenza A viruses (IAV) have been repeatedly demonstrated to circulate in wild suid populations. In this study, serum samples were collected from 2618 free-ranging wild boars in a protected area of Northern Italy between 2007 and 2014, and firstly screened by enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies against IAV. The ELISA-positive samples were further tested by hemagglutination inhibition (HI) assays performed using antigen strains representative of the four major swine IAV (sIAV) lineages circulating in Italy: avian-like swine H1N1, pandemic-like swine H1N1, human-like swine H1N2 and human-like swine H3N2. An overall seroprevalence of 5.5% (145/2618) was detected by ELISA, with 56.7% (80/141) of screened sera tests positive by HI assay. Antibodies against H1N1 subtypes were the most prevalent beginning in 2009—with the highest detection in the first quarter of the year—until 2013, although at a low level. In addition, antibodies to H3N2 subtype were found during six years (2007, 2009, 2010, 2011, 2012 and 2014) whereas H1N2 antibodies were detected in 2012 only. Of the HI-positive samples, 30% showed reactivity to both H1N1 and H3N2 subtypes. These results provide additional insight into the circulation dynamics of IAV in wild suid populations, suggesting the occurrence of sIAV spillover events from pigs to wild boars.

Prevalence and Molecular Characterization of Mycobacterium bovis in Slaughtered Cattle Carcasses in Burkina Faso; West Africa

This cross-sectional study was conducted at the slaughterhouses/slabs of Oudalan and Ouagadougou in Burkina Faso, between August and September 2013. It aimed at determining the prevalence of bovine tuberculosis (bTB) suggestive lesions in slaughtered cattle carcasses and to identify and characterize the mycobacteria isolated from these lesions. A thorough postmortem examination was conducted on carcasses of a total of 2165 randomly selected cattle. The overall prevalence of bTB suggestive lesions was 2.7% (58/2165; 95% CI 2.1–3.5%). Due to the low number of positive samples, data were descriptively presented. The lesions were either observed localized in one or a few organs or generalized (i.e., miliary bTB) in 96.6% (n = 57) and 3.4% (n = 2), respectively. The identified mycobacteria were M. bovis (44.4%, n = 20), M. fortuitum (8.9%, n = 4), M. elephantis (6.7%, n = 3), M. brumae (4.4%, n = 2), M. avium (2.2%, n = 1), M. asiaticum (2.2%, n = 1), M. terrae (2.2%, n = 1), and unknown non-tuberculous mycobacteria (NTM) (11.1%, n = 5). Moreover, eight mixed cultures with more than one Mycobacterium species growing were also observed, of which three were M. bovis and M. fortuitum and three were M. bovis and M. elephantis. In conclusion, M. bovis is the predominant causative agent of mycobacterial infections in the study area. Our study has identified a base to broaden the epidemiological knowledge on zoonotic transmission of mycobacteria in Burkina Faso by future studies investigating further samples from humans and animals, including wild animals employing molecular techniques.

The Association between Palmer Drought Severity Index Data and Tuberculosis-like Lesions Occurrence in Mediterranean Hunted Wild Boars

Simple Summary

Climate is one of the most influential factors in the dynamics of tuberculosis in the Mediterranean Iberic wildlife population. In this study, we aim to address how drought as a risk factor influences the occurrence of Tuberculosis-like lesions (TBL) in wild boar inspected in the field. With this focus, our study contributes to pointing out the importance of periods of drought in the increased TBL occurrence in wild boars inspected in the field in the subsequent season. The results of our study allow hunting managers to be advised, in advance, on whether they should adopt extra protective measures when they are aware of the presence of periods of drought. This climate trait can become an alert sign for increased TBL occurrence in the following season, allowing for the implementation of a feasible, timely, and effective measures to control TB in the wild boar population.

Abstract

In the Iberian Peninsula, the prevalence of tuberculosis differs for each region and for different wild disease hosts and the region affected by a Mediterranean climate will be the most affected. The Mediterranean Iberic regions have a favourable ecosystem for the development of Mycobacterium tuberculosis complex agents, where habitat, population dynamics, and climate (especially drought) are important factors affecting the high prevalence of tuberculosis in the wild boar population. Our objective was to study the association between the Palmer Drought Severity Index (PDSI) and the occurrence of tuberculosis-like lesions (TBL) in wild boar during nine hunting seasons (2008/09 to 2016/17) in Idanha-a-Nova County. To this end, statistical analysis revealed a significant association (p < 0.05) between the occurrence of TBL in wild boar in Idanha-a-Nova County and the analysed risk factor—previous season with periods of drought—which indicated that, when one season experiences some periods of drought, the probability of TBL occurrence in wild boars was 1.2 (OR = 1.2) times higher in the next hunting season than when there were no periods of drought. Therefore, our study contributes to the discovery of a positive effect of periods of drought on the transmission of tuberculosis in Iberian wildlife.

Symptomatic and Asymptomatic Protist Infections in Hospital Inpatients in Southwestern China

Cryptosporidium spp., Entamoeba histolytica, Giardia duodenalis, and Blastocystis sp. infections have been frequently reported as etiological agents for gastroenteritis, but also as common gut inhabitants in apparently healthy individuals. Between July 2016 and March 2017, stool samples (n = 507) were collected from randomly selected individuals (male/female ratio: 1.1, age range: 38–63 years) from two sentinel hospitals in Tengchong City Yunnan Province, China. Molecular (PCR and Sanger sequencing) methods were used to detect and genotype the investigated protist species. Carriage/infection rates were: Blastocystis sp. 9.5% (95% CI: 7.1–12.4%), G. duodenalis 2.2% (95% CI: 1.1–3.8%); and E. histolytica 2.0% (95% CI: 0.9–3.6%). Cryptosporidium spp. was not detected at all. Overall, 12.4% (95% CI: 9.7–15.6) of the participants harbored at least one enteric protist species. The most common coinfection was E. histolytica and Blastocystis sp. (1.0%; 95% CI: 0.3–2.2). Sequence analyses revealed that 90.9% (10/11) of the genotyped G. duodenalis isolates corresponded to the sub-assemblage AI. The remaining sequence (9.1%, 1/11) was identified as sub-assemblage BIV. Five different Blastocystis subtypes, including ST3 (43.7%, 21/48), ST1 (27.1%, 13/48), ST7 (18.8%, 9/48), ST4 (8.3%, 4/48), and ST2 (2.1%, 1/48) were identified. Statistical analyses confirmed that (i) the co-occurrence of protist infections was purely random, (ii) no associations were observed among the four protist species found, and (iii) neither their presence, individually or jointly, nor the patient’s age was predictors for developing clinical symptoms associated with these infections. Overall, these protist mono- or coinfections are asymptomatic and do not follow any pattern.

Investigation of Mycobacterium bovis and Metastrongylus sp. co-infection and its relationship to tuberculosis lesions' occurrence in wild boars

Animal tuberculosis (aTB) is a zoonotic disease characterized by granulomatous lesions on affected tissues, occurring as a consequence of immunological response to infection. Mycobacterium bovis, the main causative agent of aTB, was investigated in Brazilian wild boars with 37.7 % (29/77) positivity. Among these animals, most had no macroscopic tuberculosis-like lesions (89.6 %; 26/29). The existence of co-infections, which may alter an individual's immune response to an immunological challenge, could influence the formation of tuberculosis lesions. Therefore, we investigated Metastrongylus sp. and aTB co-infection to seek an explanation for the absence of macroscopic lesions in aTB. Of the tested animals, 77.9 % (60/77) had Metastrongylus sp., however, there was no association between its occurrence and the pattern of aTB lesions. The absence of tuberculous lesions in infected animals is worrisome, especially to hunters who handle their carcasses, potentially assuming that the animal is healthy. Studies evaluating other possibilities that can explain the absence of lesions in infected animals should be carried out to better understand these findings.

Mycoplasma hyopneumoniae in free-living wild boars in Paraná, Brazil

This is the first study conducted in Paraná, Brazil, to investigate Mycoplasma hyopneumoniae (Mhyo) infection in free-living wild boars. Eighty-eight wild boars were managed by authorized controllers between 2017 and 2019 in the state of Paraná in southern Brazil. Management georeferencing, sex, and weight were recorded for each animal. The presence of Mhyo antibodies in wild boar serum samples was evaluated using a commercial indirect ELISA kit. The presence of enzootic pneumonia-like gross lesions was evaluated, and the observed macroscopic lesions were subjected to immunohistochemistry (IHC). The Chi-square test and the intensity of the association with the odds ratio and 95% confidence interval were used to evaluate the differences in the qualitative variables between groups (sex and municipality). Juvenile wild boars exhibited a higher seroprevalence than older ones (p = 0.005). The Teixeira Soares municipality differed in Mhyo seroprevalence in comparison with Castro (p < 0.001), Ponta Grossa (p = 0.004), and Carambeí (p < 0.001). Females were 6.79 times more likely to present consolidation lesions than males (p = 0.004). Among the evaluated lung samples with injuries, 57.1% (8/14) and 53.8% (7/13) were Mhyo positive by IHC in Castro and Ponta Grossa, respectively, confirming that the identified macroscopic lesions were caused by Mhyo. This study demonstrates the circulation of Mhyo in free-living wild boars, which raises concerns regarding the epidemiological role of this animal species for the spread of the pathogen.

Health profile of free-range wild boar (Sus scrofa) subpopulations hunted in Santa Catarina State, Brazil

Wild boars represent a potential dissemination source of important pathogens to public and animal health, since they can host several pathogens. This study aimed to evaluate the health profile of wild boars hunted for population control in the state of Santa Catarina (SC), south of Brazil. For this study, tissue and blood samples were collected from 61 wild boars hunted from October 2017 to November 2018. All 61 serum samples were screened for antibodies by different assays, presenting the following seroprevalence: 52.4% for porcine circovirus type 2 (PCV2); 21.3% for Leptospira spp.; 19.7% for Mycoplasma hyopneumoniae; 13.1% for hepatitis E virus (HEV); and 9.8% for influenza A virus (IAV). No seroreaction was observed for Brucella spp. and classical swine fever virus (CSFV). At necropsy, the main lesions observed were evidence of pulmonary metastrongylid parasites, haemorrhagic lymph nodes and white-spotted liver. Histopathological analyses mainly showed interstitial pneumonia, bronchopneumonia and bronchi-associated lymphoid tissue (BALT) hyperplasia. There was a significant association between metastrongylid parasitism and BALT hyperplasia in lungs. Pathological findings of wild boars indicate that the assessed individuals were not exposed to notifiable diseases, such as CSFV, African swine fever virus and foot-and-mouth disease, which cause economic damage by non-tariff trade barriers. However, the detection of antibodies against PCV2 and M. hyopneumoniae, pathogens that impact commercial production, indicates the circulation of these agents, with frequency variation in wild populations. This shows the potential risk of pathogen transmission among domestic swine populations and free-living ones. The detection of antibodies against zoonotic agents such as HEV, IAV and Leptospira spp., other than characterizing the pathogens' circulation in these populations, suggests a potential risk to public health and pig farming, depending on the interactions established with the environment, humans and domestic swine.

Gut commensal bacteria show beneficial properties as wildlife probiotics

Probiotics are noninvasive, environmentally friendly alternatives for reducing infectious diseases in wildlife species. Our aim in the present study was to evaluate the potential of gut commensals such as lactic acid bacteria (LAB) as wildlife probiotics. The LAB selected for our analyses were isolated from European badgers (Meles meles), a wildlife reservoir of bovine tuberculosis, and comprised four different genera: Enterococcus, Weissella, Pediococcus, and Lactobacillus. The enterococci displayed a phenotype and genotype that included the production of antibacterial peptides and stimulation of antiviral responses, as well as the presence of virulence and antibiotic resistance genes; Weissella showed antimycobacterial activity owing to their ability to produce lactate and ethanol; and lactobacilli and pediococci modulated proinflammatory phagocytic responses that associate with protection against pathogens, responses that coincide with the presence of immunomodulatory markers in their genomes. Although both lactobacilli and pediococci showed resistance to antibiotics, this was naturally acquired, and almost all isolates demonstrated a phylogenetic relationship with isolates from food and healthy animals. Our results show that LAB display probiotic benefits that depend on the genus, and that lactobacilli and pediococci are probably the most obvious candidates as probiotics against infectious diseases in wildlife because of their food-grade status and ability to modulate protective innate immune responses.

Tuberculosis in the wild boar: Frequentist and Bayesian estimations of diagnostic test parameters when Mycobacterium bovis is present in wild boars but at low prevalence

The Eurasian wild boar (Sus scrofa) is increasingly considered as a relevant actor in the epidemiology of animal tuberculosis (TB). Therefore, monitoring TB in this species is key when establishing comprehensive control schemes for this disease still present in Europe. No data are available on direct and indirect TB diagnostic methods in wild boars in epidemiological contexts where TB is endemic in cattle and detected in wild boars at low prevalence. We aimed to estimate and compare sensitivity and specificity values for bacterial culture, PCR and three commercial ELISAs, i.e. the TB ELISA-VK (using the bPPD antigen), INgezim TB Porcine and IDEXX M. bovis Ab Test (both using the MPB83 and MPB70 antigens), under field conditions in France. We used frequentist methods, with bacteriology as the gold standard, and a Bayesian formulation of the latent class analysis (LCA), without using a gold standard. Submandibular lymph nodes and sera from 495 wild boars hunter-harvested in three endemic areas (Aquitaine region, Côte d’Or region, and Corsica region) were collected between 2014 and 2016. Only eight individuals were positive for M. bovis by bacteriology (1.61%; CI_95% 0.70–3.51%). The LCA method provided high specificities (99.2%; CI_95% 98.2–99.8% for INgezim TB Porcine and 99.7%; CI_95% 98.8–100% for IDEXX M. bovis Ab Test) and sensitivities (78.5%; CI_95% 65.1–88.8% for INgezim TB Porcine and 83.9%; CI_95% 58.9–97.2% for IDEXX M. bovis Ab Test) for both ELISAs using the MPB83 and MPB70 antigens. Bacterial culture showed limited sensitivity (42.8%; CI_95% 19.0–70.6%), estimated as the probability of a positive result in an animal exposed to M. bovis. PCR and ELISA using the bPPD antigens demonstrated high specificities, and sensitivities intermediates between culture and the ELISAs using the MPB83 and MPB70 antigens. These results suggest that ELISA tests using the MPB83 and MPB70 antigens are useful to detect and monitor TB exposure of wild boar populations in field conditions in France.

Nasal shedding of Mycobacterium tuberculosis in wild boar is related to generalised tuberculosis and concomitant infections

BACKGROUND

Wild boar is an important reservoir of Mycobacterium tuberculosis variant bovis, the main causative agent of bovine tuberculosis (bTB). A proportion of tuberculosis (TB)-affected wild boars shed M tuberculosis by nasal route, favouring the maintenance of bTB in a multihost scenario. The aim of this work was to assess if M tuberculosis nasal excretion is influenced by factors commonly associated with high TB prevalence in wild boar.

METHODS

TB diagnosis and M tuberculosis isolation were carried out in 112 hunted wild boars from mid-western Spain. The association between the presence of M tuberculosis DNA in nasal secretions and explanatory factors was explored using partial least squares regression (PLSR) approaches.

RESULTS

DNA from M tuberculosis was detected in 40.8 per cent nasal secretions of the TB-affected animals. Explanatory factors provided a first significant PLSR X's component, explaining 25.70 per cent of the variability observed in M tuberculosis nasal shedding. The presence of M tuberculosis in nasal secretions is more probable in animals suffering from generalised TB and mainly coinfected with Metastrongylus species and porcine circovirus type 2, explaining nearly 90 per cent of the total variance of this model.

CONCLUSION

Measures aiming to control these factors could be useful to reduce M tuberculosis shedding in wild boar.

Bovine tuberculosis disturbs parasite functional trait composition in African buffalo

Novel parasites can have wide-ranging impacts, not only on host populations, but also on the resident parasite community. Historically, impacts of novel parasites have been assessed by examining pairwise interactions between parasite species. However, parasite communities are complex networks of interacting species. Here we used multivariate taxonomic and trait-based approaches to determine how parasite community composition changed when African buffalo (Syncerus caffer) acquired an emerging disease, bovine tuberculosis (BTB). Both taxonomic and functional parasite richness increased significantly in animals that acquired BTB than in those that did not. Thus, the presence of BTB seems to catalyze extraordinary shifts in community composition. There were no differences in overall parasite taxonomic composition between infected and uninfected individuals, however. The trait-based analysis revealed an increase in direct-transmitted, quickly replicating parasites following BTB infection. This study demonstrates that trait-based approaches provide insight into parasite community dynamics in the context of emerging infections.

A metaproteomics approach reveals changes in mandibular lymph node microbiota of wild boar naturally exposed to an increasing trend of Mycobacterium tuberculosis complex infection

Constraints in the characterization of microbiota community that circulates in the host have limited the extent of co-infection studies in natural populations. In this study, we used a metaproteomics approach to characterize the mandibular lymph nodes microbiota of wild boar (Sus scrofa) naturally exposed to an increasing trend of Mycobacterium tuberculosis complex (MTC) infection. Our results showed a reduction in microbiota diversity and changes in the composition, structure and functionality of the microbiota community associated with an increase in tuberculosis prevalence, from 45% in 2002/06 to 83% in 2009/12. These temporal changes were accompanied by an increase in the relative abundance of Babesia, Theileria and Pestivirus genera and a decrease in the Ascogregarina and Chlorella. A positive association was also evidenced between the prevalence of tuberculosis and the presence of microbial proteins responsible for carbohydrate transport and metabolism. Our findings suggest MTC-host-microbiota interactions at the population level, which may occur in order to ensure sufficient metabolic resources for MTC survival, growth and transmission. We strongly recommend the use of metaproteomics when studying microbiota communities in wildlife populations, for which traditional diagnostic techniques are limited and in which new organisms with a pathogenic potential for domestic animals and humans may appear.

Prevalence of Intestinal Parasites and Associated Factors among Pulmonary Tuberculosis Suspected Patients Attending University of Gondar Hospital, Gondar, Northwest Ethiopia

Introduction

Intestinal parasitic infections are among the major public health problems in developing countries. Hence, it is significant to explore coinfection with intestinal parasites and pulmonary tuberculosis because coinfection increases the complexity of control and prevention of pulmonary tuberculosis and parasitic diseases.

Objective

To assess the prevalence of intestinal parasites among pulmonary tuberculosis suspected patients.

Method

Institutional based cross-sectional study was conducted at University of Gondar Hospital from March to May, 2017. Stool samples were taken from each participant and examined by direct microscopy and concentration technique. Descriptive statistics was performed and chi-square test was used to show the association between variables. P values of <0.05 were considered statistically significant.

Results

Intestinal parasites were detected in 50 (19.6%) among a total of 256 pulmonary tuberculosis suspected patients who were included in the study, whereas the prevalence of pulmonary tuberculosis was 16.8% (43/256). Pulmonary tuberculosis and intestinal parasite coinfection was detected in 5 (2.0%) of the participants. The most prevalent intestinal parasites infection in this study was Ascaris lumbricoides, 15 (5.85%), followed by Entamoeba histolytica/dispar, 14 (5.46%), and Hookworm, 13 (5.1%).

Conclusion

The prevalence of intestinal parasites and their coinfection rate with pulmonary tuberculosis among pulmonary tuberculosis suspected patients were considerable.

Suidae and Tayassuidae

The Suidae and Tayassuidae live on all continents except Antarctica. True wild boars were indigenous to Europe and Asia and are the ancestors to the domestic pig; with whom they share the same scientific name Sus scrofa. Wild boars have been introduced to the Americas and many islands. Because of the close genetic relationship, in many areas they have interbred with domestic pigs and formed considerable populations of feral suids that represent wild boar and feral pig crosses. Wild suid populations are relatively hardy and most disease research has been focused on their potential as a reservoir for diseases of concern for commercial pig production. The Togian Island babirusa, pygmy hog, Visayan warty pig, Javan warty pig, and Chacoan peccary are endangered. For all species, hunting, habitat loss, and hybridization are important threats to conservation.

Helminth-microparasite co-infection in wildlife: lessons from ruminants, rodents and rabbits

Co-infection is now recognized as the natural state of affairs in most hosts and co-infecting parasites interact in a variety of ways that can impact host health and parasite fitness. Interactions between helminths and microparasites have captured particular attention in this regard owing to the ubiquity of helminth infections in many host populations. The mechanistic underpinnings and health implications of co-infection are typically studied in laboratory and clinical settings, but recently studies of wild species have begun to tackle similar issues. Case studies from three wild mammal groups-ruminants, rodents and rabbits-serve to highlight how wild studies are contributing to the broader co-infection literature. This work suggests that wildlife research can generate new and unique insights about helminth-microparasite co-infection that are fostered in part by studying parasite interactions in a natural context. For this reason, increased integration of wild studies with research in human, laboratory and veterinary animal populations can help pave the way towards a more complete understanding of the issue of co-infection.

How does supplementary feeding affect endoparasite infection in wild boar?

Supplementary feeding is widely used in game management but may aid the transmission of parasites. Firstly, feeding sites attract animals and may be regarded as high-risk areas for parasite transmission. Secondly, high host population densities resulting from and supported by supplementary feeding, as well as accumulation of parasites in the environment, may increase parasite prevalence. Our aim was to investigate whether host density or the number of feeding sites drives endoparasite infection in an Estonian wild boar (Sus scrofa) population. For this, we collected wild boar faeces from forests, and soil samples from supplementary feeding sites in central and south-eastern Estonia. The role of host density and number of feeding sites on both the risk and mean abundance of endoparasite infection was modelled using generalized linear models (GLM). The presence of biohelminths in faecal samples was associated with both wild boar and feeding site density, whereas the presence of Eimeria sp. oocysts in faecal samples was only associated with wild boar density. Helminth eggs were found more often from the soil of active and abandoned feeding sites than from control areas. This could reflect parasitic contamination or indicate that supplementary feeding sites are suitable habitat for soil-dwelling nematodes. These results suggest that the effects of supplementary feeding on parasite prevalence in wild boar are mediated by the characteristics of parasite life cycles.

What We Have Learned and What We Have Missed in Tuberculosis Pathophysiology for a New Vaccine Design: Searching for the "Pink Swan"

This is a call to encourage the search for a new vaccine to stop the progression of Mycobacterium tuberculosis infection to tuberculosis (TB) disease. TB is a highly discreet and stigmatized disease, with a massive impact on human health. It has killed 1.2 billion people in the last 200 years and still kills 1.5 million people per year. Over the last 20 years, the TB vaccine field has experienced spectacular developments, and we have learned about (1) the importance of the Th1 response in controlling infection, mainly against RD1 and Ag85 antigens; (2) the stability of the antigenic repertoire; (3) the dynamics of M. tuberculosis granulomas; or (4) the link between typical and atypical pulmonary TB and the immune status of the host. However, we still do not (1) know how to avoid M. tuberculosis infection and reinfection; (2) understand the major role of the increase in lesion size in progression from infection to disease; (3) the role of interlobular septa in encapsulating pulmonary lesions; or (4) the role of neutrophilic infiltration and an exaggerated inflammatory response in the development of TB disease. These are strong reasons to pursue new, imaginative proposals involving both the antibody response and a balanced, tolerant immune response that averts progression toward TB. So far, the scientific mindset has been quite monolithic and has mainly focused on the stimulation of conventional T cells. But this approach has failed. For that reason, we are seeking unconventional perspectives to find a “pink swan,” a more efficacious and safer vaccine candidate.

Is There a Risk for Introducing Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Through the Legal Importation of Pork?

Since the appearance of porcine reproductive and respiratory syndrome virus (PRRSV) in the late 1980s, the virus has become endemic throughout the world, with only the countries of Sweden, Switzerland, Finland, Norway, Australia, and New Zealand historically free of PRRS virus. Biosecurity is maintained largely through restrictions on the importation of pigs and semen. The risk for a PRRSV outbreak via the legal importation of fresh/chilled/frozen pork from PRRSV-positive countries remains controversial. However, examination of the historical record shows that countries retained a PRRSV-negative status during the importation of more than 500,000 tons of fresh/chilled/frozen pork from PRRSV-positive trading partners. This review describes some of the unique properties of PRRSV, including the poor stability of the virus in the environment, the low probability for airborne transmission, and the inability to sustain infections in feral swine, which make PRRSV a poor candidate for disease introduction through the legal importation of pork.

Evidence of low prevalence of mycobacterial lymphadenitis in wild boars (Sus scrofa) in Poland

Mycobacterium spp. and Rhodococcus equi are generally regarded as the main causes of lymphadenitis in pigs and wild boars. In Poland, mycobacterial submandibular lymphadenitis was first diagnosed in a wild boar in 2012 but Mycobacterium spp. infections are also present in the Polish population of European bison (Bison bonasus). The prevalence of lymphadenitis in Polish wild boars has been found to 8.4% (95% CI 6.2–11.3%) and it has been proved that R. equi is not an important cause of purulent lesions in these animals. The current study was carried out to assess the prevalence of mycobacterial lymphadenitis in the Polish wild boar population. Submandibular lymph nodes with purulent lesions collected from 38 wild boars in 2010/2011 and negative for R. equi were included. Calculations based on the hypergeometric approximation were used to determine the probability that at least one positive individual would be detected if the infection had been present at a prevalence greater than or equal to the design prevalence. All 38 samples were negative for Mycobacterium spp. [0% (95% CI 0, 9.2%)]. Epidemiological analysis showed that the true prevalence was 95% likely to be lower than 10%. In conclusion, mycobacterial lymphadenitis seems to occur rarely in wild boars in Poland. Due to the presence of Mycobacterium spp. infections in other wildlife, the surveillance of mycobacterial infections in wild animals in Poland remains an important issue.

Pseudorabies virus infection (Aujeszky's disease) in an Iberian lynx (Lynx pardinus) in Spain: a case report

Background

The only natural hosts of Pseudorabies virus (PRV) are members of the family Suidae (Sus scrofa scrofa). In species other than suids infection is normally fatal. In these mammals, including carnivores, PRV typically causes serious neurologic disease. The endangered Iberian lynx (Lynx pardinus) is a wild feline endemic to south-western Europe (Iberian Peninsula). The Iberian lynx was found to be the world’s most endangered felid species in 2002. In wild felines, PRV infection has only been previously reported once in a Florida panther in 1994. No seropositive lynxes have ever been found, nor has PRV been detected in dead Iberian lynxes to date.

Case presentation

We describe the first reported case of pseudorabies in an Iberian lynx (Lynx pardinus). Pseudorabies was diagnosed in a young wild Iberian lynx from Extremadura (SW Spain) by histopathological examination, immunohistochemistry, polymerase chain reaction (PCR) and sequence analysis. Gross lesions included alopecia of the ventral neck, bloody gastro-intestinal contents and congestion of the brain. Histopathological analysis showed a moderate nonsuppurative meningoencephalitis with diffuse areas of demyelination, necrotizing gastritis and enteritis of the small intestine. Pseudorabies virus (PRV) antigen was found in neuronal and non-neuronal cells of the brain, tonsils, and gastric glandular epithelial cells by immunohistochemical analysis. The presence of the virus in the brain was confirmed by nested PCR. The sequence analysis of the 146 bp fragment (from the viral glycoprotein B gene) showed that the amplified sequence matched (with 100% identity) the PRV genome. Furthermore, specific DNA from glycoprotein D and E encoding-genes was detected by conventional and real-time PCR, respectively, confirming the latter that this infection was produced by a wild-type PRV strain.

Conclusions

This study supports the suspicion that PRV could infect the Iberian lynx. The detection of PRV in a dead Iberian lynx suggests that the virus may have a negative impact on the survival of endangered lynxes in the wild. However, because this is the first verified instance of lynx mortality resulting from pseudorabies, its true impact on the population is unknown.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0938-7) contains supplementary material, which is available to authorized users.

Oxidative Stress in Wild Boars Naturally and Experimentally Infected with Mycobacterium bovis

Reactive oxygen and nitrogen species (ROS-RNS) are important defence substances involved in the immune response against pathogens. An excessive increase in ROS-RNS, however, can damage the organism causing oxidative stress (OS). The organism is able to neutralise OS by the production of antioxidant enzymes (AE); hence, tissue damage is the result of an imbalance between oxidant and antioxidant status. Though some work has been carried out in humans, there is a lack of information about the oxidant/antioxidant status in the presence of tuberculosis (TB) in wild reservoirs. In the Mediterranean Basin, wild boar (Sus scrofa) is the main reservoir of TB. Wild boar showing severe TB have an increased risk to Mycobacterium spp. shedding, leading to pathogen spreading and persistence. If OS is greater in these individuals, oxidant/antioxidant balance in TB-affected boars could be used as a biomarker of disease severity. The present work had a two-fold objective: i) to study the effects of bovine TB on different OS biomarkers (namely superoxide dismutase (SOD), catalasa (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and thiobarbituric acid reactive substances (TBARS)) in wild boar experimentally challenged with Mycobacterium bovis, and ii) to explore the role of body weight, sex, population and season in explaining the observed variability of OS indicators in two populations of free-ranging wild boar where TB is common. For the first objective, a partial least squares regression (PLSR) approach was used whereas, recursive partitioning with regression tree models (RTM) were applied for the second. A negative relationship between antioxidant enzymes and bovine TB (the more severe lesions, the lower the concentration of antioxidant biomarkers) was observed in experimentally infected animals. The final PLSR model retained the GPX, SOD and GR biomarkers and showed that 17.6% of the observed variability of antioxidant capacity was significantly correlated with the PLSR X’s component represented by both disease status and the age of boars. In the samples from free-ranging wild boar, however, the environmental factors were more relevant to the observed variability of the OS biomarkers than the TB itself. For each OS biomarker, each RTM was defined as a maximum by one node due to the population effect. Along the same lines, the ad hoc tree regression on boars from the population with a higher prevalence of severe TB confirmed that disease status was not the main factor explaining the observed variability in OS biomarkers. It was concluded that oxidative damage caused by TB is significant, but can only be detected in the absence of environmental variation in wild boar.

Association between vitamin D supplementation and severity of tuberculosis in wild boar and red deer

Tuberculosis (TB) is a chronic disease affecting humans and other mammal species. Severity of TB caused by Mycobacterium tuberculosis in humans seems to be influenced by nutritional factors like vitamin D3 intake. However, this relationship has been scarcely studied in cattle and other mammals infected with Mycobacterium bovis. The aim of this work was to assess if wildlife reservoirs of M. bovis show different levels of TB severity depending on the level of vitamin D found in serum after supplementation with vitamin D3. Forty hunted wildlife mammals were included in this study: 20 wild boar and 20 red deer. Ten wild boar and ten red deer had been supplemented with a vitamin D3-enriched food, whereas the remaining animals had received no supplementation. TB diagnosis was carried out in each animal based on microbiological isolation of M. bovis. Animals infected with M. bovis were then classified as animals with localized or generalized TB depending on the location and dissemination of the lesions. Furthermore, serum levels of vitamin D2 and D3 were determined in each animal to evaluate differences not only between supplemented and non-supplemented animals but also between those with localized and generalized TB. Levels of vitamin D3 found in both, supplemented wild boar and red deer, were significantly higher than those found in the non-supplemented animals. Interestingly, higher levels of vitamin D3 were observed in animals suffering localized TB when compared to animals with generalized TB suggesting that vitamin D3 concentration correlates negatively with TB severity in these wildlife reservoirs.

Impact of co-infections with enteric pathogens on children suffering from acute diarrhea in southwest China

Background

Acute diarrhea is a global health problem, resulting in high morbidity and mortality in children. It has been suggested that enteric pathogen co-infections play an important role in gastroenteritis, but most research efforts have only focused on a small range of species belonging to a few pathogen groups. This study aimed to assess the impact of co-infections with a broad range of enteric pathogens on children aged below five years who suffer from acute diarrhea in southwest China.

Method

A total of 1020 subjects (850 diarrhea cases and 170 healthy controls) were selected from four sentinel hospitals in Kunming, Yunnan province, southwest China, from June 2014 to July 2015. Stool specimens were collected to detect five virus (rotavirus group A, RVA; norovirus, NoV; Sapovirus, SaV; astrovirus, As; and adenovirus, Ad), seven bacterial (diarrheagenic Escherichia coli, DEC; non-typhoidal Salmonella, NTS; Shigella spp.; Vibrio cholera; Vibrio parahaemolyticus; Aeromonas spp.; and Plesiomonas spp.), and three protozoan (Cryptosporidium spp., Giardia lamblia, and Blastocystis hominis, B. hominis) species using standard microbiologic and molecular methods. Data were analyzed using the partial least square regression technique and chi-square test.

Results

At least one enteric pathogen was detected in 46.7 % (n = 397) of acute gastroenteritis cases and 13.5 % (n = 23) of healthy controls (χ² = 64.4, P < 0.05). Single infection with RVA was associated with acute diarrhea (26.5 % vs. 5.8 %, P < 0.05). The prevalence of a single infection with B. hominis in diarrhea cases was higher than in healthy controls (3.1 % vs. 0.5 %, OR = 4.7, 95 % CI: 1.01–112.0). Single infection with NoV GII was not associated with diarrhea (4.4 % vs. 3.5 %, OR = 1.2, 95 % CI: 0.5–3.3). Single infections with bacterial species were not observed. The prevalence of co-infections with two enteric pathogens in diarrhea cases was higher than in asymptomatic children (20.1 % vs. 5.3 %, P < 0.05). RVA-NoV GII was the most common co-infection in symptomatic children (4.4 %), with it aggravating the severity of diarrhea.

Conclusions

Although it is clear that RVA has an overwhelming impact on diarrhea illnesses in children, co-infection with other enteric pathogens appears to also aggravate diarrhea severity. These findings should serve as evidence for public health services when planning and developing intervention programs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0157-2) contains supplementary material, which is available to authorized users.

Fitness responses to co-infestation in fleas exploiting rodent hosts

To understand mechanisms behind positive interspecific co-occurrences in flea infracommunities, we asked whether co-infestation results in an increase of flea fitness (quantity and/or quality of the offspring). We studied reproductive performance of Xenopsylla ramesis and Parapulex chephrenis when they exploited their characteristic host (Meriones crassus and Acomys cahirinus, respectively) either alone or together with another species. We used egg production, the number of new imagoes, pre-imaginal survival and egg size as fitness-related variables and predicted that fitness will be higher in fleas feeding in mixed- than in single-species groups. In both fleas, mean number of eggs produced per female flea did not depend on experimental treatment. No effect of single- vs mixed-species infestation on the mean number of new imagoes per female and the number of emerged imagoes per egg was found for X. ramesis, whereas both these numbers were higher in mixed- than in single-species groups for P. chephrenis. X. ramesis produced eggs of similar size independently of treatment, whereas eggs produced by P. chephrenis in mixed-species groups were significantly larger than eggs produced in single-species groups. We conclude that an increase in reproductive performance as a response to co-infestation may be one of the mechanisms behind aggregative structure of flea infracommunities. However, this response may vary among flea species.

Uses and limitations of faecal egg count for assessing worm burden in wild boars

The most widely used technique to assess helminth infection in both domestic and wild mammals is the faecal egg count (FEC). Most efforts to test the reliability of FEC as a proxy for parasite load are in small ruminant studies and limited work has evaluated the use of FEC in pigs. The aim of this study was to explore whether FEC is a reliable indicator of helminth load, and to evaluate the effects of sample storage on FEC accuracy in 59 wild boars. Though FEC was useful for assessing most helminth infections (e.g., Metastrongylus spp., Ascaris suum, Trichuris suis), stomach nematodes were often missed. The accuracy of FEC decreased over time, and thus it is recommended that samples be processed within 5 days of collection.