Evolutionary loss of inflammasomes in the Carnivora and implications for the carriage of zoonotic infections.

Zoonotic pathogens, such as COVID-19, reside in animal hosts before jumping species to infect humans. The Carnivora, like mink, carry many zoonoses, yet how diversity in host immune genes across species affect pathogen carriage is poorly understood. Here, we describe a progressive evolutionary downregulation of pathogen-sensing inflammasome pathways in Carnivora. This includes the loss of nucleotide-oligomerization domain leucine-rich repeat receptors (NLRs), acquisition of a unique caspase-1/-4 effector fusion protein that processes gasdermin D pore formation without inducing rapid lytic cell death, and the formation of a caspase-8 containing inflammasome that inefficiently processes interleukin-1ß. Inflammasomes regulate gut immunity, but the carnivorous diet has antimicrobial properties that could compensate for the loss of these immune pathways. We speculate that the consequences of systemic inflammasome downregulation, however, can impair host sensing of specific pathogens such that they can reside undetected in the Carnivora.

Does Virus-Receptor Interplay Influence Human Coronaviruses Infection Outcome?

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the third (following SARS-CoV and Middle East Respiratory Syndrome-CoV) zoonotic coronavirus that has crossed the species barrier in the 21st century, resulting in the development of serious human infection. The punishing effect of the recent outbreak of pandemic disease termed COVID-19 (coronavirus disease-19) caused by SARS-CoV-2 impelled us to gather the facts about the nature of coronaviruses. First, we introduce the basic information about coronavirus taxonomy, structure, and replication process to create the basis for more advanced consideration. In the following part of this review, we focused on interactions between the virus and the receptor on the host cell, as this stage is the critical process determining the species and tissue tropism, as well as clinical course of infection. We also illuminate the molecular basis of the strategy used by coronaviruses to cross the species barrier. We give special attention to the cellular receptor's interaction with S protein of different CoVs (dipeptidyl peptidase IV and angiotensin-converting enzyme 2), as well as the cellular proteases involved in proteolysis of this protein. These factors determine the virus entry and replication; thus, even fine quantitative or qualitative differences in their expression may crucially affect outcomes of infection. Understanding virus biology and characterization of the host factors involved in coronavirus transmission and pathogenesis may offer novel options for development of efficient therapeutic and preventive strategies.

Histopathological Survey on Sarcocystis Species Infection in Slaughtered Cattle of Zabol-Iran

Objective: Sarcocystosis is an important zoonotic protozoal disease with worldwide distribution and wide range of hosts. The aim of the present study was to determine the intensity of Sarcocystis spp. infection and to show histopathological features of their cystic lesions in slaughtered cattle of Zabol- Iran. Methods: From April to September 2018, 500 tissue samples from esophagus, heart, diaphragm, tongue and masticatory muscles were prepared from 100 slaughtered cattle. All samples were fixed in 10% neutral buffered formalin and routine tissue processing protocol was performed. Results: The microscopic results showed that 92.2% of specimens had thin-walled cysts of S. cruzi and 14% had thick-walled Sarcocystis (S. hirsuta and S. hominis) but macrocyst was only observed in one cattle. The positivity rate of thin walled cysts was 58.8% for heart, 13.9% for masticatory muscles, 10.2% for tongue, 9.3% for esophagus and 7.8% for diaphragm. The positivity rate of thick walled cysts was 32.8% for esophagus, 28.6% for tongue, 22.9% for heart, 15.7% for masticatory muscles and 0% for diaphragm, which could represent either S. hominis or S. hirsuta. The most infected tissue was heart and the least infected tissue was diaphragm. Thin walled cysts (S. cruzi) were mostly found in heart and were less found in diaphragm. However, thick-walled cysts (S. hirsuta and S. hominis) were mostly detected in esophagus. No thick-walled cysts were found in diaphragm muscle. Conclusion: A high positivity rate of sarcocystosis in slaughtered cattle in Zabol abattoir revealed heavily environmental contamination of Sistan region by this important parasitic disease.

Mycobacterium avium paratuberculosis and Mycobacterium avium complex and related subspecies as causative agents of zoonotic and occupational diseases.

Mycobacterium avium complex (MAC) and Mycobacterium avium paratuberculosis (MAP) cause zoonotic infections transmitted by birds and livestock herds. These pathogens have remained as serious economic and health threats in most areas of the world. As zoonotic diseases, the risk of development of occupational disease and even death outcome necessitate implementation of control strategies to prevent its spread. Zoonotic MAP infections include Crohn's disease, inflammatory bowel disease, ulcerative colitis, sarcoidosis, diabetes mellitus, and immune-related diseases (such as Hashimoto's thyroiditis). Paratuberculosis has classified as type B epidemic zoonotic disease according to world health organization which is transmitted to human through consumption of dairy and meat products. In addition, MAC causes pulmonary manifestations and lymphadenitis in normal hosts and human immunodeficiency virus (HIV) progression (by serotypes 1, 4, and 8). Furthermore, other subspecies have caused respiratory abscesses, neck lymph nodes, and disseminated osteomyelitis in children and ulcers. However, the data over the occupational relatedness of these subspecies is rare. These agents can cause occupational infections in susceptible herd breeders. Several molecular methods have been recognized as proper strategies for tracking the infection. In this study, some zoonotic aspects, worldwide prevalence and control strategies regarding infections due to MAP and MAC and related subspecies has been reviewed.

Brucella neotomae Recapitulates Attributes of Zoonotic Human Disease in a Murine Infection Model.

Members of the genus Brucella are Gram-negative pathogens that cause chronic systemic infection in farm animals and zoonotic infection in humans. Study of the genus Brucella has been hindered by the need for biosafety level 3 select agent containment. Brucella neotomae, originally isolated from the desert pack rat, presented an opportunity to develop an alternative, non-select agent experimental model. Our prior in vitro work indicated that the cell biology and type IV secretion system (T4SS) dependence of B. neotomae intracellular replication were similar to observations for human-pathogenic select agent Brucella species. Therefore, here, we investigated the pathobiology of B. neotomae infection in the BALB/c mouse. During a sustained infectious course, B. neotomae replicated and persisted in reticuloendothelial organs. Bioluminescent imaging and histopathological and PCR-based analysis demonstrated that the T4SS contributed to efficient early infection of the liver, spleen, and lymph nodes; granuloma formation and hepatosplenomegaly; and early induction of Th1-associated cytokine gene expression. The infectious course and pathologies in the murine model showed similarity to prior observations of primate and native host infection with zoonotic Brucella species. Therefore, the B. neotomae BALB/c infection model offers a promising system to accelerate and complement experimental work in the genus Brucella.

Prolactin as immune cell regulator in Toxocara canis somatic larvae chronic infection.

Toxocariasis is a zoonotic disease produced by ingestion of larval Toxocara spp. eggs. Prolactin (PRL) has been considered to have an important role in Toxocara canis infection. Recent evidence has found that PRL directly can increase parasite growth and differentiation of T. canis The present study, evaluated the effect of high PRL levels on the immune system's response and parasites clearance in chronic infection. Our results showed that hyperprolactinemia did not affect the number of larvae recovered from several tissues in rats. Parasite-specific antibody production, showed no difference between the groups. Lung tissue presented eosinophilic granulomas typical of a chronic infection in all the experimental groups. Flow cytometry analysis was made in order to determine changes in the percentage of innate and adaptive immune cell subpopulations in the spleen, peripheric (PLN) and mesenteric (MLN) lymphatic nodes. The results showed a differential effect of PRL and infection on different immune compartments in the percent of total T cells, T helper cells, T cytotoxic cells, B cells, NK cells, and Tγδ cells. To our knowledge, for the first time it is demonstrated that PRL can have an immunomodulatory role during T. canis chronic infection in the murine host.

Bartonella henselae infection in diverse clinical conditions in a tertiary care hospital in north India.

BACKGROUND & OBJECTIVES: : Bartonella henselae causes infections which closely resemble febrile illness and chronic diseases such as tuberculosis and haematological malignancies. There are not many studies on Bartonella infections from India. The present study was undertaken to diagnose B. henselae infection in diverse clinical conditions in a tertiary care hospital in north India. METHODS: A total of 145 patients including those with fever and lymphadenopathy, infective endocarditis and neuroretinitis were enrolled in the study. Whole blood, serum and lymph node aspirate and valvular vegetations if available, were obtained. Samples were plated on chocolate agar and brain-heart infusion agar containing five per cent fresh rabbit blood and were incubated at 35°C for at least four weeks in five per cent CO2with high humidity. Immunofluorescent antibody assay (IFA) was done for the detection of IgM antibodies in the serum using a commercial kit. Whole blood was used to perform polymerase chain reaction (PCR) for the citrate synthase gene (gltA). RESULTS: IFA was positive in 11 of 140 (7.85%) patients and PCR was positive in 3 of 140 (2.14%) patients. Culture was negative in all the cases. A higher incidence of Bartonella infection was seen in patients with fever and lymphadenopathy (n=30), seven of whom were children. In ophthalmological conditions, four cases were IFA positive. INTERPRETATION & CONCLUSIONS: The present study shows that the threat of Bartonella infection is a reality in India. It is also an important treatable cause of fever and lymphadenopathy in children. Serology and PCR are useful tests for its diagnosis. Clinicians should consider. BARTONELLA: infection in the differential diagnosis of febrile illnesses and chronic diseases.

Tissue distribution and cell tropism of Brucella canis in naturally infected canine foetuses and neonates.

Brucella canis infection is an underdiagnosed zoonotic disease. Knowledge about perinatal brucellosis in dogs is extremely limited, although foetuses and neonates are under risk of infection due to vertical transmission. In this study, immunohistochemistry was used to determine tissue distribution and cell tropism of B. canis in canine foetuses and neonates. Diagnosis of B. canis in tissues of naturally infected pups was based on PCR and sequencing of amplicons, bacterial isolation, and immunohistochemistry, whose specificity was confirmed by laser capture microdissection. PCR positivity among 200 puppies was 21%, and nine isolates of B. canis were obtained. Tissues from 13 PCR-positive puppies (4 stillborn and 9 neonates) presented widespread immunolabeling. Stomach, intestines, kidney, nervous system, and umbilicus were positive in all animals tested. Other frequently infected organs included the liver (92%), lungs (85%), lymph nodes (69%), and spleen (62%). Immunolabeled coccobacilli occurred mostly in macrophages, but they were also observed in erythrocytes, epithelial cells of gastrointestinal mucosa, renal tubules, epidermis, adipocytes, choroid plexus, ependyma, neuroblasts, blood vessels endothelium, muscle cells, and in the intestinal lumen. These results largely expand our knowledge about perinatal brucellosis in the dog, clearly demonstrating a pantropic distribution of B. canis in naturally infected foetuses and neonates.

[Cat scratch disease - a neglected zoonosis]. / Nemoc z kocicího skrábnutí - opomíjená zoonóza.

Cat scratch disease is a relatively rare infection that is caused by the bacterium Bartonella henselae. This disease occurs after cat scratch or bite. The course of the disease depends on the patients immunity status. In immunocompetent patients, the disease typically runs as a lymph node syndrome. Sometimes, mild general symptoms may appear, or the course can be atypical with a more serious clinical manifestation involving various organs. In immunocompromised patients, Bartonella henselae can cause bacillary angiomatosis or peliosis with a severe course.

A Human Case of Zoonotic Dog Tapeworm, Dipylidium caninum (Eucestoda: Dilepidiidae), in China.

We described a human case of zoonotic dog tapeworm, Dipylidium caninum (Eucestoda: Dilepidiidae), rarely occurring in China. The mother of a 17 month-old boy noted the appearance of small white and active worms over a month period in her son's feces, but the boy was asymptomatic except mild diarrhea. We observed 3 tapeworm proglottids resembling cucumber seeds in his stool sample. Microscopically, each proglottid had 2 genital pores, 1 on each lateral edge, and numerous egg capsules in the uterus. The patient was successfully treated with a single oral dose of praziquantel. Adult worms were recovered in the diarrheic stool after praziquantel treatment and purgation. His family had household pet dogs for several years, and he might have acquired the infection by ingestion of infected fleas of his pet dogs. A history of dog or cat pets and flea bites may be important clues to diagnosis of D. caninum infection. The infected pets should also be treated.

[Head and neck localizations of hydatid cyst: A series of 17 cases]. / Localisations cervico-faciales du kyste hydatique : série de 17 cas.

INTRODUCTION: Head and neck localizations of hydatid cyst are very rare (1% of human cases) even in countries where echinococcosis is endemic (human sites). Our objective was to report the epidemiological, and clinical characteristics and the management of head and neck localizations of hydatid cyst. MATERIALS AND METHODS: A retrospective descriptive study of 17 cases of head and neck hydatid cysts taken in charge in our department between 2000 and 2014 was conducted. RESULTS: The mean age was 35 years. Male were slightly predominant (sex ratio: 1.12). Eighty-eight percent of the patients had regular contact with dogs and 53% were of rural origin. The soft tissues of the head and neck were involved in six patients, the parotid gland in 6 patients, the thyroid in 4 patients and the submaxillary gland in one patient. Complete surgical resection of the lesions was systematically done. Hydatid disease was confirmed in all the cases by histology. The outcome was uneventful in all the patients with a mean follow-up of 2 years. CONCLUSION: Given the lack of recommendations for the surgical treatment of head and neck hydatid cysts, we advocate a total resection of the affected organ if there is no functional risk. Otherwise, an excision of the cyst and of the surrounding tissues combined with an abundant washing-out of the residual cavity must be done, especially in case of intraoperative breaking of the cyst.

Concurrent Bartonella henselae infection in a dog with panniculitis and owner with ulcerated nodular skin lesions.

BACKGROUND: Bartonella henselae, a Gram-negative, zoonotic Alphaproteobacteria that infects erythrocytes, endothelial cells and dendritic cells, has previously been implicated as a cause of panniculitis in dogs and a human. ANIMAL AND OWNER: An 8-year-old, spayed female Labrador retriever and its 78-year-old male owner living in the same household. METHODS AND RESULTS: When preliminary and advanced testing failed to identify the cause of near-simultaneous-onset dermatological lesions, Bartonella serology, Bartonella Alphaproteobacteria growth medium (BAPGM) enrichment blood culture/PCR and immunohistochemistry were used to test specimens from the dog and owner. Bartonella henselae, genotype San Antonio 2 DNA was amplified and sequenced from the man's BAPGM enrichment blood culture and the dog's panniculitis lesion. The bacterium was visualized by immunohistochemistry in the dog's panniculitis lesion; however, neither the dog nor the owner was B. henselae seroreactive. Antibiotic therapy elicited dermatological improvement in both dog and owner. CONCLUSIONS AND CLINICAL IMPORTANCE: Bartonella henselae is an emerging zoonotic pathogen that induces granulomatous inflammatory lesions in various tissues of animals, including humans. We conclude that this bacterium had a contributory or causative role in the development of the dermatological lesions in the dog and owner.

Zoonotic anatrichosomiasis in a mother and daughter.

Zoonotic anatrichosomiasis in a mother and daughter is reported. Both presented with a 10-week history of multiple painful oral ulcers. Biopsy specimens revealed the presence of small, coiled trichuroid nematodes with distinctive morphological features, including stichocytes and paired bacillary bands. This represents an unusual infection by a zoonotic Anatrichosoma species.

Epidemiology and management of Buruli ulcer.

Buruli ulcer (Mycobacterium ulcerans infection) is a neglected tropical disease of skin and subcutaneous tissue that can result in long-term cosmetic and functional disability. It is a geographically restricted infection but transmission has been reported in endemic areas in more than 30 countries worldwide. The heaviest burden of disease lies in West and Sub-Saharan Africa where it affects children and adults in subsistence agricultural communities. Mycobacterium ulcerans infection is probably acquired via inoculation of the skin either directly from the environment or indirectly via insect bites. The environmental reservoir and exact route of transmission are not completely understood. It may be that the mode of acquisition varies in different parts of the world. Because of this uncertainty it has been nicknamed the 'mysterious disease'. The therapeutic approach has evolved in the past decade from aggressive surgical resection alone, to a greater focus on antibiotic therapy combined with adjunctive surgery.

Detection of antibodies to Toxoplasma gondii in wild animals in Brazil

Toxoplasmosis is a worldwide zoonosis caused by an obligate intracellular protozoan parasite, Toxoplasma gondii, that affects all warm-blooded animals, including wild animals. The increased number of cases of parasitic infections is mainly due to the destruction of environmental conservation areas, which is driving wild animals out of their habitats and towards urban areas. In this study, the occurrence of T. gondii infection was investigated by the modified agglutination test (MAT) in 26 different species of run over and injured wild animals that were treated at a Brazilian university veterinary hospital, from June 2007 to August 2008. Of the studied animals, six (23.1%; CI95% 11.1-42.2%) had T. gondii antibodies, with titers equal to 10 (4; 66.7%) and 40 (2; 33.3%). The species Pseudalopex vetulus, Cerdocyon thous, Hydrochoerus hydrochaeris and Tapyrus terrestris had titers of 10, while Alouatta caraya and Puma concolor had titers of 40. There was no significant association regarding age, gender or purpose of care (p > 0.05). Carnivorous, herbivorous and omnivorous wild animals are potential sentinels of human toxoplasmosis, especially when wild felids are present, maintaining the environmental contamination.

Antibodies against rickettsiae from spotted fever groups in horses from two mesoregions in the state of Santa Catarina, Brazil / Anticorpos contra rickettsias do grupo da febre maculosa em equinos de duas mesorregiões de Santa Catarina, Brasil

Bacteria of the Rickettsia genus are agents of Brazilian Spotted Fever (BSF), a zoonotic disease which is difficult to diagnose, evolves quickly and can result in death. Antibodies against Rickettsia spp. in horses were studied, by means of Indirect Immunofluorescence Assay (IFAT ≥64), in 150 blood samples taken from animals in two Santa Catarina mesoregions (Planalto Serrano and Vale do Itajaí). The overall occurrence of Rickettsia spp. antibodies in horses was 18.66%, with cross-reactivity occurring in all positive samples for at least two of the species tested. Separately, according to the species, 25 (16.66%) samples were positive for R. rickettsii, 15 (10%) for R. parkeri, 22 (14.66%) for R. amblyommii, 23 (15.33%) for R. rhipicephali, 16 (10.66%) for R. bellii and 19 (12.66%) for R. felis. Only two animals resulted in a conclusive serodiagnosis, one for R. bellii and the other for R. rickettsii, at maximum dilutions of 1:4096 and 1:512, respectively. The occurrence of antibodies against Rickettsia spp. in horses from two mesoregions in the state of Santa Catarina indicates the movement of BSF agents in these sentinel animals and confirms the importance of studying spotted fever in the state of Santa Catarina.

Bactérias do gênero Rickettsia são agentes da Febre Maculosa Brasileira (FMB), uma doença zoonótica, de difícil diagnóstico, rápida evolução e que pode levar o indivíduo à morte. Anticorpos contra Rickettsia spp. em equinos foram pesquisados, por meio da Reação de Imunofluorescência Indireta (RIFI≥64), em 150 amostras de sangue colhidas de animais em duas mesorregiões de Santa Catarina (Planalto Serrano e Vale do Itajaí). A ocorrência de anticorpos contra Rickettsia spp. observada em equinos de duas mesorregiões de Santa Catarina foi de 18,66%, ocorrendo reações cruzadas em todas as amostras positivas para, no mínimo, duas das espécies testadas. Isoladamente, de acordo com as espécies, 25 (16,66%) amostras foram positivas para R. rickettsii, 15 (10%) para R. parkeri, 22 (14,66%) para R. amblyommii, 23 (15,33%) para R. rhipicephali, 16 (10,66%) para R. bellii e 19 (12,66%) para R. felis. Somente dois animais resultaram em um sorodiagnóstico conclusivo, um para Rickettsia bellii e outro para R. rickettsii, nas diluições máximas de 1:4096 e 1:512, respectivamente. A ocorrência de anticorpos contra Rickettsia spp. em equinos de duas mesorregiões de Santa Catarina indica a circulação de agentes da FMB nestes animais sentinela e ratificam a importância do estudo da febre maculosa no estado de Santa Catarina.