Source Of Human Infection Research Articles

Gastrointestinal Parasites of Domestic Mammalian Hosts in Southeastern Iran

Gastrointestinal parasites (GIP) are a major cause of disease and production loss in livestock. Some have zoonotic potential, so production animals can be a source of human infections. We describe the prevalence of GIP in domestic mammals in Southeastern Iran. Fresh fecal samples (n = 200) collected from cattle (n = 88), sheep (n = 50), goats (n = 23), camels (n = 30), donkeys (n = 5), horse (n = 1), and dogs (n = 3) were subjected to conventional coprological examination for the detection of protozoan (oo)cysts and helminth ova. Overall, 83% (166/200) of the samples were positive for one or more GIP. Helminths were found in dogs, donkeys, sheep (42%), camels (37%), goats (30%), and cattle (19%), but not in the horse. Protozoa were found in cattle (82%), goats (78%), sheep (60%), and camels (13%), but not in donkeys, dogs, or the horse. Lambs were 3.5 times more likely to be infected by protozoa than sheep (OR = 3.5, 95% CI: 1.05-11.66), whereas sheep were at higher odds of being infected by helminths than lambs (OR = 4.09, 95% CI: 1.06-16.59). This is the first study assessing the prevalence of GIP in domestic mammals in Southeastern Iran.

Giardiasis of domestic animals and its zoonotic significance: A review

Giardiasis is the most common waterborne parasitic intestinal infection ofboth animals and humans worldwide, and it leads to significant morbidity and mortality in animals, particularly in young aged group like calves in the developing and developed world. It is a zoonotic infectious disease where animals are considered as sources of infection for humans through consumption of water and food contaminated with cysts of Giardia. Giardia species differ significantly in host range, with G. duodenalis having the broadest host range and greatest public health significance. Giardia duodenalis has eight different assemblages A through H. The disease Causes gastro intestinal disturbance, gall bladder colic and jaundice. Malabsorption and maldigestion mainly result from a diffuse shortening of epithelial microvillus. Giardia duodenalis (synonyms intestinalis, lamblia) is a flagellate binucleated protozoan, and it has two morphological forms: cysts and trophozoites. The life cycle of Giardia is direct, and the infective stage of the parasite, the cyst, is encysted when released into the feces and is immediately infectious. Trophozoites are pear-shaped, binucleate, multi-flagellated parasite forms and are the disease causing stage and colonize the upper small intestine, where they adhere to the epithelial surface and proliferate by binary fission. Infected animals, contaminated water and feed are main sources of infection. Age of animals, season of the year, area, housing, feeding, management practices are usually considered as risk factors for the occurrence of giardiasis. The infection can be transmitted by the fecal-oral route, or through contaminated food and water. To survive within the intestine, Giardia undergoes antigenic variation and few virulent factors have been identified to be responsible for the infection. These include ventral adhesive disc proteins and surface lectins, the four pairs of flagella which allow for movement and variant surface proteins. The clearance of Giardia from a host requires both innate and adaptive immunity effector mechanisms. The infection can be diagnosed by examining fecal specimens using different coproscopic techniques, serological tests and by molecular analysis. Restricting animals from surface water during periods of high cyst shedding may reduce watershed contamination. Health education on personal and environmental hygiene would help in reducing the occurrence of the infection. This review work tries to gather information on giardiasis of domestic animals with respect to its epidemiology, host immune responses, pathophysiology, distribution and its public health importance.

Migratory Wild Birds as Potential Long-Distance Transmitters of Toxoplasma gondii Infection

Toxoplasma gondii is a worldwide distributed zoonotic protozoan capable of infecting a wide range of mammals (including humans) and birds as intermediate hosts. Migratory wild birds, through interconnecting countries along their flyways, can play a role in the spatial spread of T. gondii and could contribute to its sylvatic cycle. Additionally, hunted wild birds used for meat consumption could represent a further source of human infection. To determine the presence of T. gondii in wild birds, a total of 50 individuals belonging to the Anseriformes and Charadriiformes orders were sampled during the 2021-2022 hunting season in Northern Italy. Cardiac muscle samples of three Northern shovelers (Anas clypeata), two wild mallards (A. platyrhynchos), one Eurasian teal (A. crecca), and one Northern lapwing (Vanellus vanellus) were positive for the molecular detection of T. gondii based on a targeted amplification of the B1 gene. A 14% (7/50) overall positivity was observed in the sampled population. Results from this study suggest a moderate exposure of wild aquatic birds to T. gondii, highlighting the importance of a further characterization of T. gondii in its wildlife hosts.

Characterization and Antibiotic Resistance of Listeria monocytogenes Strains Isolated from Greek Myzithra Soft Whey Cheese and Related Food Processing Surfaces over Two-and-a-Half Years of Safety Monitoring in a Cheese Processing Facility

Listeriosis is a serious infectious disease with one of the highest case fatality rates (ca. 20%) among the diseases manifested from bacterial foodborne pathogens in humans, while dairy products are often implicated as sources of human infection with Listeria monocytogenes. In this study, we characterized phenotypically and genetically by whole-genome sequencing (WGS) 54 L. monocytogenes strains isolated from Myzithra, a traditional Greek soft whey cheese (48 isolates), and swabs collected from surfaces of a cheese processing plant (six isolates) in the Epirus region of Greece. All but one strain of L. monocytogenes belonged to the polymerase chain reaction (PCR) serogroups IIa (16.7%) and IIb (81.5%), corresponding to serotypes 1/2a, 3a and 1/2b, 3b, 7, respectively. The latter was identified as a PCR-serogroup IVb strain (1.8%) of serotypes 4b, 4d, 4e. Bioinformatics analysis revealed the presence of five sequence types (STs) and clonal complexes (CCs); ST1, ST3, ST121, ST 155, ST398 and CC1, CC3, CC121, CC155, CC398 were thus detected in 1.9, 83.3, 11.0, 1.9, and 1.9% of the L. monocytogenes isolates, respectively. Antibiograms of the pathogen against a panel of seven selected antibiotics (erythromycin, tetracycline, benzylpenicillin, trimethoprim-sulfamethoxazole, ampicillin, ciprofloxacin, and meropenem) showed that 50 strains (92.6%), the six surface isolates also included, were intermediately resistant to ciprofloxacin and susceptible to the rest of the six antimicrobial agents tested, whereas strong resistance against the use of a single from three implicated antibiotics was recorded to four strains (7.4%) of the pathogen isolated from Myzithra cheese samples. Thence, the minimum inhibitory concentrations (MICs) were determined for erythromycin (MIC = 0.19 μg/mL), ciprofloxacin (MIC ≥ 0.19 μg/mL), and meropenem (MIC = 0.64 μg/mL), and finally, just one strain was deemed resistant to the latter antibiotic. The phylogenetic positions of the L. monocytogenes strains and their genetic variability were determined through WGS, whilst also stress response and virulence gene analysis for the isolates was conducted. Findings of this work should be useful as they could be utilized for epidemiological investigations of L. monocytogenes in the food processing environment, revealing possible contamination scenarios, and acquired antimicrobial resistance along the food production chain.

BACTERIAL CONTAMINATION AND BIOLOGICAL SAFETY OF BREAM AND WALLEYE IN POSTDIPLOSTOMOSIS IN THE CONDITIONS OF THE KUIBYSHEV RESERVOIR

Fish and fish products are of no small importance as an obligatory component of the human diet. This is due to the fact that fish meat has a high nutritional and nutritional value. However, in some cases, fish is a source of infection for humans. This is the case with some parasitoses and infections. Fish parasitoses are quite widespread, both in natural reservoirs and in pond fish farms. Often, the course of parasitosis in fish is complicated by the addition of secondary microflora, which aggravates the pathological process and serves as a source of toxic infections for humans. The authors conducted a comparative analysis of microflora in postdiplostomosis of bream and walleye in the conditions of the Kuibyshev reservoir. During the research, an inventory of the microflora of sick fish was carried out. It is represented by microorganisms from two families - Enterobacteriaceae and Vibrionaceae and three genera Listeria, Pseudomonas, Staphylococcus. Contamination of organs and tissues of sick fish also has differences. The gills are maximally contaminated. Minimal contamination is inherent in the skin. In a fish with postdiplostomosis, the presentation is violated. In its raw, insufficiently boiled, fried, dried salted form, it is dangerous for humans as a source of helminthic invasion. The contamination of pathogenic and conditionally pathogenic microflora creates prerequisites for the development of toxic infections in humans when eating such fish.

Pilot study of the productivity and Salmonella seroprevalence in pigs administered organic acids.

Control of Salmonella in pig/pork production is important to protect public health because pork is one of the main sources of human infection. Moreover, antimicrobial use in pig farms should be kept low to minimize development and transmission of antimicrobial resistance. This pilot study evaluated the productivity and Salmonella seroprevalence in pigs administered organic acids (OA) compared to pigs given growth promoters in one farm in Antioquia, Colombia. Two groups each consisting of 60 pigs of 6-weeks of age were studied for 4 months. One group was provided feed and water with OA (Selko pH® and Selacid®), whereas the other group (control) received antimicrobial growth promoters according to routine feeding practices (tylosin and zinc bacitracin). Blood samples were taken three times (T1-T3) and pigs were weighted five times to calculate daily weight gain (DWG) and feed conversion ratio (FCR). Initially when the pigs were 6 weeks old (T1), the Salmonella seroprevalence was 1.7% in both groups. When the pigs were 11 weeks old (T2), the seroprevalence was significantly lower in pigs provided OA compared to the control group (19 vs. 47%, P < 0.001), whereas when the pigs were 23 weeks old (T3), the seroprevalence did not differ between the groups (62 vs. 77%; P = 0.075). The cumulative DWG was significantly higher in the intervention group than in the control group (713 vs. 667 g/day; P < 0.001). The cumulative FCR did not differ between groups (2.80 vs. 2.77; P = 0.144). The pilot study indicates that cleaning the water pipes and administrating OA improve productivity in pigs and delay exposure to Salmonella spp. when compared with growth promoters. Thus, OA could replace antimicrobial growth promoters and reduce antimicrobial use and resistance. However, the study should be repeated before firmer conclusions can be drawn.

Japanese Encephalitis outbreak in Assam, Northeastern India, January to August 2022

An outbreak of Japanese encephalitis (JEV) was detected in Assam, Northeast India, on July 1st, 2022. The source of human infection is known to be zoonotic transmission from culicine mosquitoes through bites. A total of 434 cases of JEV were recorded between July 1 and September 23, 2022, in 17 separate districts within Assam, India. The precise demographics of these JEV cases remain unknown. The case fatality rate in Assam during this outbreak was 21.43% (93); however, underreporting may occur. JEV is vaccine-preventable, and a vaccine was introduced under the Universal Immunization Programme (UIP) in endemic states to cover children at risk, but not adults. Such serious outbreaks have occurred in the past, with an outbreak in 2006 causing 6061 cases and 1500 deaths. Reports from the current outbreak suggest the cause of the outbreak may be due to prolonged floods resulting in water stagnation in Assam. An unusual feature of the current outbreak is the relatively high CFR and significant neurological involvement. Some key questions include: what is the demographic distribution of JEV cases in Assam? What is the vaccine coverage in Assam? How protective is the JEV vaccine?

Whole genome sequence-based characterisation of Shiga toxin-producing Escherichia coli isolated from game meat originating from several European countries

Game meat is becoming increasingly popular but may be contaminated with pathogenic bacteria such as Shiga toxin-producing Escherichia coli (STEC). STEC cause gastrointestinal illnesses including diarrhoea, haemorrhagic colitis (HC), and the haemolytic uremic syndrome (HUS). The aim of this study was to assess the occurrence of STEC in 92 meat samples from chamois (n = 2), red deer (n = 27), roe deer (n = 38), and wild boar (n = 25), from Switzerland and other European countries. After enrichment, Shiga-toxin encoding genes (stx) were detected by PCR in 78 (84%) of the samples and STEC were isolated from 23 (25%) of the same samples. Nine different serotypes and eight different sequence types (STs) were found, with O146:H28 ST738 (n = 10) and O110:H31 ST812 (n = 5) predominating. None of the STEC belonged to the so-called top-five serogroups O26, O103, O111, O145, and O157. Subtyping of stx identified stx1c (n = 9), stx2a (n = 1), stx2b (n = 19), stx2e (n = 2), and stx2g (n = 1). Additional virulence factors (VFs) comprised ehx (n = 12), iha (n = 21), sta1 (n = 1), and subAB (n = 19). None of the isolates contained the eae gene. Twenty-one STEC contained VFs associated with extra-intestinal pathogenic E. coli (ExPEC). Overall, the pathogenic potential of STEC in game meat is moderate, though the isolation of one STEC strain carrying stx2a, and of STEC/ExPEC hybrids suggests a role of game meat as a potential source of STEC infections in humans. Therefore, detailed knowledge of the safe handling and preparation of game meat is needed to prevent foodborne infections.

A High Viral Load in Urine Correlates With Acute Kidney Injury and Poor Outcomes in Hospitalized Patients With Severe Fever With Thrombocytopenia Syndrome: A Noninvasive and Convenient Prognostic Marker.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with an extensive geographical distribution and high mortality rate. To date, the role of SFTS virus (SFTSV) in urine is still elusive. We aimed to explore the relationship between urinary bunyavirus and acute kidney injury (AKI) and mortality in patients with SFTS. Urine samples were collected from 102 patients to quantify SFTSV load in urine (U-SFTSV). Patient renal function was evaluated on admission. Receiver operating characteristic (ROC) curve and logistic regression analysis were performed to evaluate the predictive value of U-SFTSV. Viral infectivity assays in Vero cells were performed from 10 urine samples. The U-SFTSV level was positively correlated with SFTSV load in plasma (r = 0.624) and indicators of renal damage. The U-SFTSV level was identified as an independent risk factor for SFTS-associated AKI (odds ratio, 3.631; P = .019). The U-SFTSV showed great value in predicting the fatal outcome of SFTS patients with high area under curve (0.881). The Kaplan-Meier survival comparison showed that patients with U-SFTSV levels greater than 6379 copies/mL were at a higher risk of death within 28 days after onset. In addition, 4 urine samples with high U-SFTSV levels were infectious. Our large cohort study identified that the U-SFTSV level is a novel convenient and noninvasive predictive biomarker for incidence of AKI and poor outcome of patients with SFTS. Urine specimens could be a source of SFTSV infection in humans.

Occurrence and molecular characterization of Enterocytozoon bieneusi in wild and domestic animal species in Portugal.

The phylum Microsporidia encompasses a diverse group of obligate, intracellular, and spore-forming organisms able to infect a wide range of animal hosts. Among them, Enterocytozoon bieneusi is the most frequently reported species in humans and animals. Little is known about the presence and epidemiology of E. bieneusi in wildlife. We investigated E. bieneusi occurrence and genetic diversity in wild and domestic mammals, through molecular-detection methods, from different regions across Portugal. A total of 756 samples were collected from 288, 242 and 226 wild carnivores, wild ungulates, and domestic animals, respectively. Overall, eight specimens were E. bieneusi-positive (1.1%, 8/756) obtained from five wild (Iberian lynx, Iberian wolf, red fox, stone marten, and wild boar) and one domestic (sheep) host. Nucleotide sequence analysis identified four genotypes of E. bieneusi, Type IV, Wildboar3, BEB6 and PtEbIX. Three of those genotypes belong to Groups 1 (Type IV and Wildboar3) and 2 (BEB6), which are known to contain genotypes capable of infecting a variety of hosts, including humans, highlighting their public health importance. PtEbIX belongs to the dog-specific Group 11. This study represents the first, largest and most comprehensive molecular-based epidemiology survey carried out in Portugal in wild and domestic animals to date and the first worldwide identification of E. bieneusi in wolf species. Our study showed that wild carnivores and ungulates are reservoirs of zoonotic genotypes of E. bieneusi, establishing their role in maintaining the sylvatic cycle of this parasite while representing a potential source of infection for humans and domestic animals.

Detection and Molecular Characterization of Giardia and Cryptosporidium spp. Circulating in Wild Small Mammals from Portugal.

Cryptosporidium spp. and Giardia spp. are important diarrhea-causing protozoan parasites worldwide that exhibit broad host ranges. Wild small mammals can harbor host-adapted and potentially zoonotic species of both parasites. The aim of this study was to investigate Cryptosporidium spp. and Giardia spp. in wild rodents and shrews in Portugal, focusing on the protist's occurrence and genetic diversity. Molecular screening by PCR at the small subunit (SSU) rRNA gene locus of 290 fecal samples from wood mice (Apodemus sylvaticus), southwestern water voles (Arvicola sapidus), Cabrera's voles (Microtus cabrerae), Lusitanian pine voles (Microtus lusitanicus), Algerian mice (Mus spretus) and greater white-toothed shrews (Crocidura russula) in Northeast Portugal revealed the low occurrence of Cryptosporidium spp. (1%) and high occurrence of Giardia spp. (32.8%). The analysis revealed that "species" was the only significant factor associated with the increasing probability of Giardia spp. infection, with the highest prevalence reported in southwestern water voles and Lusitanian pine voles. Cryptosporidium and Giardia species determination at the SSU rRNA gene locus revealed C. muris and G. microti as the only circulating species, respectively. Subtyping of the glutamate dehydrogenase (gdh) and beta-giardin (bg) genes provided evidence of the high genetic diversity within the G. microti clade. This study suggests that rodent-adapted G. microti occurs to a large extent in cricetid hosts and supports the limited role of wild rodents and shrews as natural sources of human infections in Northeast Portugal regarding the investigated parasites. Moreover, this is the first record of G. microti in southwestern water voles, Lusitanian pine voles, Algerian mice, wood mice and Cabrera's voles and C. muris in Cabrera's voles. Finally, this study improves the database of sequences relevant for the sequence typing of G. microti strains and provides new insights about the epidemiology of Giardia spp. and Cryptosporidium spp. in wild rodents and shrews, two parasite genera of high importance for public and animal health.

Proteome-Wide Screening of Potential Vaccine Targets against Brucella melitensis.

The ongoing antibiotic-resistance crisis is becoming a global problem affecting public health. Urgent efforts are required to design novel therapeutics against pathogenic bacterial species. Brucella melitensis is an etiological agent of brucellosis, which mostly affects sheep and goats but several cases have also been reported in cattle, water buffalo, yaks and dogs. Infected animals also represent the major source of infection for humans. Development of safer and effective vaccines for brucellosis remains a priority to support disease control and eradication in animals and to prevent infection to humans. In this research study, we designed an in-silico multi-epitopes vaccine for B. melitensis using computational approaches. The pathogen core proteome was screened for good vaccine candidates using subtractive proteomics, reverse vaccinology and immunoinformatic tools. In total, 10 proteins: catalase; siderophore ABC transporter substrate-binding protein; pyridoxamine 5'-phosphate oxidase; superoxide dismutase; peptidylprolyl isomerase; superoxide dismutase family protein; septation protein A; hypothetical protein; binding-protein-dependent transport systems inner membrane component; and 4-hydroxy-2-oxoheptanedioate aldolase were selected for epitopes prediction. To induce cellular and antibody base immune responses, the vaccine must comprise both B and T-cells epitopes. The epitopes were next screened for antigenicity, allergic nature and water solubility and the probable antigenic, non-allergic, water-soluble and non-toxic nine epitopes were shortlisted for multi-epitopes vaccine construction. The designed vaccine construct comprises 274 amino acid long sequences having a molecular weight of 28.14 kDa and instability index of 27.62. The vaccine construct was further assessed for binding efficacy with immune cell receptors. Docking results revealed that the designed vaccine had good binding potency with selected immune cell receptors. Furthermore, vaccine-MHC-I, vaccine-MHC-II and vaccine-TLR-4 complexes were opted based on a least-binding energy score of -5.48 kcal/mol, 0.64 kcal/mol and -2.69 kcal/mol. Those selected were then energy refined and subjected to simulation studies to understand dynamic movements of the docked complexes. The docking results were further validated through MMPBSA and MMGBSA analyses. The MMPBSA calculated -235.18 kcal/mol, -206.79 kcal/mol, and -215.73 kcal/mol net binding free energy, while MMGBSA estimated -259.48 kcal/mol, -206.79 kcal/mol and -215.73 kcal/mol for TLR-4, MHC-I and MHC-II complexes, respectively. These findings were validated by water-swap and entropy calculations. Overall, the designed vaccine construct can evoke proper immune responses and the construct could be helpful for experimental researchers in formulation of a protective vaccine against the targeted pathogen for both animal and human use.

Core Genome Sequencing Analysis of E. coli O157:H7 Unravelling Genetic Relatedness among Strains from Cattle, Beef, and Humans in Bishoftu, Ethiopia

E. coli O157:H7 is a known Shiga toxin-producing Escherichia coli (STEC), causing foodborne disease globally. Cattle are the main reservoir and consumption of beef and beef products contaminated with E. coli O157:H7 is an important source of STEC infections in humans. To emphasize the cattle-to-human transmission through the consumption of contaminated beef in Bishoftu, Ethiopia, whole-genome sequencing (WGS) was performed on E. coli O157 strains isolated from three sources (cattle, beef, and humans). Forty-four E. coli O157:H7 isolates originating from 23 cattle rectal contents, three cattle hides, five beef carcasses, seven beef cuts at retail shops, and six human stools in Bishoftu between June 2017 and May 2019 were included. This study identified six clusters of closely related E. coli O157:H7 isolates based on core genome multilocus sequence typing (cgMLST) by targeting 2513 loci. A genetic linkage was observed among the isolate genomes from the cattle rectal contents, cattle hides, beef carcasses at slaughterhouses, beef at retail shops, and human stool within a time frame of 20 months. All the strains carried practically the same repertoire of virulence genes except for the stx2 gene, which was present in all but eight of the closely related isolates. All the strains carried the mdfA gene, encoding for the MdfA multi-drug efflux pump. CgMLST analysis revealed genetically linked E. coli O157:H7 isolates circulating in the area, with a potential transmission from cattle to humans through the consumption of contaminated beef and beef products.

Systematic Review and Modelling of Age-Dependent Prevalence of Toxoplasma gondii in Livestock, Wildlife and Felids in Europe

Toxoplasma gondii is a zoonotic parasite of importance to both human and animal health. The parasite has various transmission routes, and the meat of infected animals appears to be a major source of human infections in Europe. We aimed to estimate T. gondii prevalence in a selection of animal host species. A systematic literature review resulting in 226 eligible publications was carried out, and serological data were analyzed using an age-dependent Bayesian hierarchical model to obtain estimates for the regional T. gondii seroprevalence in livestock, wildlife, and felids. Prevalence estimates varied between species, regions, indoor/outdoor rearing, and types of detection methods applied. The lowest estimated seroprevalence was observed for indoor-kept lagomorphs at 4.8% (95% CI: 1.8-7.5%) and the highest for outdoor-kept sheep at 63.3% (95% CI: 53.0-79.3%). Overall, T. gondii seroprevalence estimates were highest within Eastern Europe, whilst being lowest in Northern Europe. Prevalence data based on direct detection methods were scarce and were not modelled but rather directly summarized by species. The outcomes of the meta-analysis can be used to extrapolate data to areas with a lack of data and provide valuable inputs for future source attribution approaches aiming to estimate the relative contribution of different sources of T. gondii human infection.

Detecção de Cryptosporidium sp. em ostras de cultivo e estoque natural no estado do Maranhão, Brasil

ABSTRACT: This study detected Cryptosporidium spp. in cultivated oysters and the natural oyster stock of the state of Maranhão and determine the elective tissue(s) to examine this protozoan. For this purpose, 200 cultivated oysters were purchased from the municipality of Raposa and another 100 from Paço do Lumiar. Additionally, 100 oysters were extracted from the natural stock of the municipality of Primeira Cruz, thus making up a total of 400 oysters. They were grouped into 80 pools consisting of 5 oysters each. From each pool, the gills and visceral mass were removed to obtain 160 pools, 80 pools for the gill group and another 80 for the visceral mass group. Then, DNA was extracted from each pool using a commercial kit with modifications. Subsequently, the protozoan DNA was detected using nested polymerase chain reaction. With this technique, the DNA of the protozoan under investigation was detected in 2.5% (n = 2/80) of the pools containing gills, with 1.25% of the pools (n = 1/80) belonging to the cultivation group of oysters and the other 1.25% (n = 1/80) to the natural stock. With the results obtained in this study, it was concluded that the analyzed oysters of the genus Crassostrea, from cultivation and natural stock groups, found in the state of Maranhão, were contaminated by Cryptosporidium spp. and may become potential sources of infection in humans and other animals. In addition, the gills are the elective tissue for the study of Cryptosporidium spp. in oysters.

Milk and cheese as a source of human infection

Contaminated food, including milk and dairy products, is the cause of health problems, important both from the point of view of an individual and families, populations or countries. Raw milk that has not been thermally treated and the cheeses made from it can be transmitters of many microorganisms that are dangerous to humans and can be found in the body of an infected animal. Food borne pathogens such as Campylobacter jejuni, Salmonella spp., Listeria monocytogenes and toxic (STEC) strains of E. coli can come from the cow itself or from its environment. These microorganisms can enter the milk indirectly from the environment (insufficient hygiene) and directly as a result of excretion into the milk by an infected animal. The paper describes the most important food pathogens causing food poisoning after consumption of milk (including pasteurized milk) and cheese.

Advanced Studies on Toxoplasma in Buffalo Meat

Since buffalo meat, has been demonstrated to be a potential source of human infection, a careful evaluation of the prevalence of Toxoplasma infection in this meat is needed. Tissue cysts of Toxoplasma gondii are frequently found in the skeletal muscles of buffaloes. This study evaluated the prevalence of Toxoplasma gondii in the meat juice of buffalo meat samples via several diagnostic techniques to protect public health. Peptic digestion, histopathology, and serology were performed on meat juice from 100 buffalo meat samples from local butchers and retail beef markets. Eighteen samples (18%) were suspected of the presence of bradyzoites after digestion, and were subjected to histopathology which illustrated that only six samples (6%) were suspected to be Toxoplasma tissue cysts. After that periodic acid Schiff (PAS) stain confirmed that only three samples (3%) were Toxoplasma. Finally, enzyme-linked immunosorbent assay (ELISA) asserted that those three samples were Toxoplasma gondii. This study provides significant evidence about risk of human exposure to Toxoplasma through the consumption of raw or undercooked buffalo meat potentially contaminated with infectious tissue cysts.

Trichinella infection in Serbia from 2011 to 2020: a success story in the field of One Health.

In Serbia, modern pork production systems with implemented control measures, including the detection of Trichinella larvae in meat (ISO18743), have eliminated farmed pork from pigs slaughtered at abattoirs as a source of trichinellosis. Epidemiological data from 2011 to 2020 indicate that the number of human cases and the number of infected domestic pigs has decreased significantly. Over the years, pork was the most frequent source of human infection. Cases generally occurred in small family outbreaks, and the infection was linked to consumption of raw or undercooked pork from backyard pigs. In most of the outbreaks, T. spiralis was the aetiological agent of infection, but in 2016, a large outbreak was caused by consumption of uninspected wild boar meat containing T. britovi larvae. To achieve safe pork, it is important that consumers of pork from animals raised in backyard smallholdings and of wild game meat are properly educated about the risks associated with consumption of untested meat. Laboratories conducting Trichinella testing should have a functional quality assurance system to ensure competency of analysts and that accurate and repeatable results are achieved. Regular participation in proficiency testing is needed.

Leptospirosis in Vietnam

Leptospirosis poses a serious public health problem in many countries because about 1 million people suffer annually from this severe, often fatal, infection. At present, its importance has been increasing due to development of integration processes, globalization and intensification of economic activities, inevitable anthropogenic transformation of landscapes as well as rise in number of people with occupational risk of pathogen exposure. The burden of human leptospirosis is expected to rise with demographic shifts and climate change that result in heavy rainfall and flooding. Regarding leptospirosis, Southeast Asia, including Vietnam, is among the most vulnerable global regions. The objective of the review was to analyze available published data on the spread of leptospirosis in Vietnam. More than 100 research articles were analyzed allowing to state that in Vietnam synanthropic rodents (rats), agricultural (buffaloes, cattle, pigs) and domestic animals (cats, dogs) are the main sources of leptospirosis infection in humans. It is essential that rats (cats and dogs also) in Vietnam are used for food. Among all farm animals, pigs are of maximal importance as a source of infection in humans. In Vietnam, Leptospira prevalence in pigs varies widely, up to 73%. It depends significantly on the location, farm size, age and gender of animals, etc. A large variety of Leptospira serovars have been identified in pigs in Vietnam: Tarassovi, Bratislava, Australis, Javanica, Autumnalis, Grippotyphosa, and some others. Official Vietnam reporting of leptospirosis cases based on clinical data does not reflect the real-life incidence rate in humans. However, the available seroprevalence studies reveal that, on average, about 10% of the Vietnamese population are infected with Leptospira. Work in agriculture is the dominant risk factor for acquiring this infection. The highest Leptospira seroprevalence rates were detected in farmers, 63.2%. Serovar diversity is typical for pathogenic Leptospira circulating in Vietnam. In humans, the most frequent are antibodies to Hebdomadis, Wolffi and Icterohaemorrhagiae, but the frequency varied markedly across the country depending on the site, possibly with relation to the environment, as well as with economic activity of the local population. In Vietnam, geographic, climatic and social differences between northern, central and southern regions contribute to the specificity of local leptospirosis epidemiology. This emphasizes the advisability of developing special measures for leptospirosis prevention taking into account regional peculiarities.

Detection of Toxoplasma gondii-specific antibodies in pigs using an oral fluid-based commercial ELISA: Advantages and limitations

Toxoplasma gondii is a major food-borne parasite and undercooked meat of infected pigs represents an important source of infection for humans. Since infections in pigs are mostly subclinical, adequate diagnostic tests for use at the farm level are pursued. Oral fluid (OF) was shown to be a promising matrix for direct and indirect detection of infections with various pathogens in pigs. The objective of this study was to assess whether T. gondii infections in pigs could be diagnosed using an indirect ELISA kit adapted for OF samples (OF-ELISA). Routine serology and OF-immunoblot (IB) were used as standards for the comparison. For this, serial OF samples from sows (n = 8) and fatteners (n = 3) experimentally inoculated with T. gondii oocysts, individual field samples from potentially exposed sows (n = 9) and pooled OF samples from potentially exposed group-housed fatteners (n = 195 pig groups, including 2,248 animals) were analysed for antibodies against T. gondii by ELISA. For individual animals, OF-ELISA exhibited a relative diagnostic specificity of 97.3% and a relative diagnostic sensitivity of 78.8%. In experimentally infected animals, positive OF-ELISA results were observed from 1.5 weeks post inoculation (pi) until the end of the experimental setup (8 to 30 weeks pi); however, values below the estimated cut-off were occasionally observed in some animals despite constant seropositivity. In potentially exposed individual animals, OF- and serum-ELISA results showed 100% agreement. In group-housed fatteners, antibodies against T. gondii could be reliably detected by OF-ELISA in groups in which at least 25% of the animals were seropositive. This OF-ELISA, based on a commercially available serum-ELISA, may represent an interesting non-invasive screening tool for detecting pig groups with a high exposure to T. gondii at the farm level. The OF-ELISA may need further adjustments to consistently detect individual infected pigs, probably due to variations in OF antibody concentration over time.