Diarrhoea-causing enteric protist species in intensively and extensively raised pigs (Sus scrofa domesticus) in Southern Spain. Part II: Association with Hepatitis E virus susceptibility.

Enteropathogenic parasites can infect a wide range of mammals, including humans, supposing an important zoonotic risk. Hepatitis E virus (HEV) is an emerging foodborne pathogen of increasing public health relevance, affecting both humans and animal populations. Because both microorganisms share faecal-oral transmission route they may constitute an excellent model to evaluate the interplay between them. Thus, we aim to evaluate the viral-parasite interactions at the enteric interface in swine. We included pigs of two different breeds farming in South Spain under different production systems. We compared the HEV prevalence by the presence of Giardia duodenalis, Cryptosporidium spp., Balantioides coli, Blastocystis sp. and Enterocytozoon bieneusi in faecal samples. The HEV prevalence was 13.1 (62 out 475, 95% CI: 10.2-16.4). Those pigs infected with Cryptosporidium spp. showed a higher prevalence of HEV (30.8 vs. 12%; p = .012). In the same way, animals bearing E. bieneusi seem to have a higher rate of HEV infection (24.2 vs. 12.2%; p = .06). According to their location in the gut, animals bearing intracellular enteroparasites showed a higher HEV prevalence than those uninfected (29.6 vs. 12.7%; p = .038), meanwhile those carrying extracellular enteroparasites had a lower likelihood to be infected by HEV than those uninfected (12.1 vs. 23.1%; p = .071). Those animals bearing both types of enteroparasites showed a similar prevalence of HEV infection than those exhibiting negative for both (20.8 vs. 26.1%; p = .763). Our study provides evidence that intracellular and extracellular enteroparasites modulate the susceptibility to HEV infection in pigs. Meanwhile, the presence of extracellular enteroparasites shows a protective effect on the risk of HEV acquisition in swine, whereas intracellular enteroparasites seems to have the opposite effect, favouring the HEV infection.

Diarrhoea-causing enteric protist species in intensively and extensively raised pigs (Sus scrofa domesticus) in Southern Spain. Part I: Prevalence and genetic diversity.

Numerous protist species are shared between humans and pigs. Among those, Giardia duodenalis, Cryptosporidium spp. and Balantioides coli have a clear public and animal health significance. For others such as Enterocytozoon bieneusi and Blastocystis sp., their impact on animal health has not been fully established. Little information is currently available on the molecular diversity of these protists in swine populations. To fill this gap, we molecularly assessed G. duodenalis, Cryptosporidium spp., B. coli, Blastocystis sp. and E. bieneusi in faecal samples from Iberian and Large White pigs raised under different (intensive and/or extensive) management systems in southern Spain. A total of 151 extensively raised Iberian pigs, 140 intensively raised Iberian pigs, and 184 intensively raised Large White pigs were investigated. Blastocystis sp. was the agent most prevalently found (47.8%), followed by B. coli (45.5%), G. duodenalis (10.7%), E. bieneusi (6.9%), and Cryptosporidium spp. (5.5%). Blastocystis sp. was significantly less prevalent in intensively raised Iberian pigs (22.9%) than in their extensively raised counterparts (51.0%) or in intensively raised Large White pigs (64.1%). A significantly higher prevalence was found for G. duodenalis, Cryptosporidium spp., and E. bieneusi in Large White pigs than Iberian pigs. Balantioides coli was similarly distributed (40.0-51.1%) in all three investigated swine populations. Sequence analyses revealed the presence of G. duodenalis assemblage E, two Cryptosporidium species (Cryptosporidium scrofarum and Cryptosporidium suis), B. coli (genotypes A and B), Blastocystis sp. (ST1, ST3, and ST5), and E. bieneusi (EbpA, EbpC, EbpD, O, and a novel genotype named PigSpEb2). Novel genotype PigSpEb2 was found alone or in combination with EbpA. Data suggest a widespread exposure to protist enteroparasites in domestic pig populations irrespectively of breed and raising management system. Many of the species/genotypes identified have a zoonotic potential and might represent a public health concern.

Risk factors associated with hepatitis E virus in pigs from different production systems.

Pigs are considered important reservoirs of HEV and so constitute a major risk of transmission to humans, either via direct contact or by consuming raw or undercooked contaminated pork products. Once the scale of this disease on European pig farms has been estimated, the identification of risk factors associated with HEV infection in these species could help determine contingency strategies to minimize the risk of transmission to humans. Our objective was to evaluate risk factors associated with HEV in pigs under different production systems. We included 1040 pigs from 26 farms. The prevalence of HEV infection in the study population, evaluated by RT-qPCR, was calculated, then studied according to animal and farm characteristics. Factors associated with HEV infection were analyzed by multivariate analysis. One hundred and seventy-two pigs were infected by HEV, which gave an individual prevalence of 16.5% (95% CI: 14.4%-18.9%). Factors associated with higher prevalence of HEV infection were: extensive farming [23.9%; OR = 2.239 (1.036-4.837)], absence of sanitary ford [33.8%; OR = 3.597 (1.649-7.850)], no quarantine period [20.8%; OR = 2.723 (1.450-5.112)], and contact with domestic species [24.5%; OR = 3.893 (1.453-10.431)]. Our evidence showed that pigs reared on extensive farms are at a higher risk of HEV infection than those reared intensively. The use of control measures could reduce the risk of HEV infection in pigs and minimize the risk of zoonotic transmission.

Hepatitis E Virus (HEV) Infection in Anti-HEV Immunoglobulin G-Carrying Patients After Successful Hepatitis C Virus Treatment: Reactivation or Reinfection?

Although hepatitis E virus (HEV) is regarded as a self-limiting infection and anti-HEV antibodies seem to protect against reinfection, its pathogenesis is not well established. We describe 2 cases of acute symptomatic HEV infection after hepatitis C therapy in patients carrying anti-HEV immunoglobulin G antibodies, raising 2 major questions: reactivation or reinfection?

Immunohistochemical study of macrophage and cytokine dynamics in the gut of scrapie-infected mice.

To study numerical changes in intestinal macrophages and variations in cytokine production by immune cells in the intestine, conventional C57BL/6J mice were orally infected with the Rocky Mountain Laboratory strain of scrapie. Animals were sacrificed at different timepoints, and samples were taken and processed by routine methods for morphological and immunohistochemical analysis. The results point to a possible role for macrophages in the uptake and transport of the infective agent to Peyer's patches. The observed increase in macrophage numbers in subepithelial sites, taken in conjunction with a drop in tumour necrosis factor-alpha production at these sites, suggests a possible secretory inhibition that could be induced by the disease-associated prion protein (PrPd). On the other hand, cytokine dynamics indicated the presence of an impaired Th1-Th2 cell mediated response, which could facilitate the spread of PrPd to the central nervous system. Further research is required to confirm these hypotheses.

Role of hepatic macrophages during the viral haemorrhagic fever induced by African Swine Fever Virus.

To ascertain the role played by the various liver monocyte-macrophage populations in the course of a viral hemorrhagic fever, fifteen pigs were inoculated intramuscularly with the highly virulent isolate of African Swine Fever Virus (ASFV) España-70 and slaughtered at 1-7 days post-inoculation (dpi). Samples of liver were fixed in different solutions and routinely processed for morphological, immunohistochemical and ultrastructural studies. Viral antigen (vp73) was detected from 3 dpi onward, mainly in circulating monocytes of sinusoid and Kupffer's cells (KC), as well as in portal macrophages and hepatocytes from 5 dpi. Anti-SWC3 immunolabelled cells were increased from 1 dpi, peaking between 3 and 5 dpi, thereafter declining until the end of the experiment. The significant increase in the number of sinusoidal circulating monocytes and KC expressing IL-1alpha, TNFalpha and IL-6 from 1 dpi, confirmed the secretory activation of these cells. The results show that in the course of an ASFV-induced hemorrhagic syndrome, hepatic macrophage populations undergo major quantitative and biosynthetic changes prior to virus detection, suggesting the existence of a mechanism by which the virus concentrates infectable cells, which subsequently spread the virus around the body.