Outbreaks of Disease Associated with Food Imported into the United States, 1996-20141.

The proportion of US food that is imported is increasing; most seafood and half of fruits are imported. We identified a small but increasing number of foodborne disease outbreaks associated with imported foods, most commonly fish and produce. New outbreak investigation tools and federal regulatory authority are key to maintaining food safety.

Pathobiology of Heterakis gallinarum mono-infection and co-infection with Histomonas meleagridis in layer chickens.

Little is known about the induction and modulation of gut-associated immune reactions after nematode infection in the chicken. The objective of the present study was to compare the pathogenesis, induction of immune reactions and electrophysiological changes of the gut after mono-infection with Heterakis gallinarum and after dual infection with H. gallinarum and Histomonas meleagridis in layer chickens. In two experiments 3-week-old chickens were inoculated with embryonated H. gallinarum eggs, which were positive for H. meleagridis. While birds of the first experiment were left untreated, those of the second experiment were treated with dimetridazol to prevent H. meleagridis co-infection. Mild to moderate histological lesions and local immune reactions with a significant increase in CD4(+), CD8α(+), TCRαß(+) and TCRδγ(+) cells in the lamina propria and induction of the T-helper type 2 (Th2) cytokine interleukin-13 dominated the H. gallinarum immune response at 2 weeks post infection. Co-infection with H. gallinarum and H. meleagridis induced an increase in mRNA expression of the T-helper type 1 (Th1) cytokine interferon-γ, a decrease in splenic CD4(+) cells and severe destruction of the caecal mucosa in association with strong T-cell infiltration in the caecal lamina propria. There was no obvious effect on the chloride secretion of the caecal epithelium, which was investigated once the mucosa had almost recovered from the infection, in either experiment. These results suggest that the local T-cell reactions to nematode infections in chickens may be comparable with mammals and may be shifted from a Th2-dominated to a Th1-dominated response when accompanied by a protozoan infection.

Dysbiosis of fecal microbiota in cats with naturally occurring and experimentally induced Tritrichomonas foetus infection.

The protozoal pathogen Tritrichomonas foetus infects the colon of domestic cats and is a major cause of chronic colitis and diarrhea. Treatment failure is common, but antibiotics may improve clinical signs in a subset of cats, leading researchers to question involvement of the colonic microbiota in disease pathogenesis. Studies performed in women with venereal Trichomonas vaginalis infections have revealed that dysbiosis of host microbiota contributes to pathogenicity with similar findings also found in mice with intestinal Tritrichomonas musculis The aim of this study was to characterize differences in the fecal microbiota of cats with and without naturally occurring T. foetus infection and in a group of kittens prior to and after experimentally induced infection. Archived fecal DNA from cats undergoing testing for T. foetus infection (n = 89) and experimentally infected kittens (n = 4; at pre-, 2 weeks, and 9 weeks post-infection) were analyzed by sequencing of 16S rRNA genes. Amongst the naturally infected population, the genera Megamonas and Helicobacter were significantly increased in prevalence and abundance in cats testing positive for T. foetus infection. In the group of four experimentally infected kittens, fecal samples post-infection had significantly lower abundance of genus Dialister and Megamonas and greater abundance of the class Betaproteobacteria and family Succinivibrionaceae. We hypothesize that T. foetus promotes dysbiosis by competition for fermentable substrates used by these bacteria and that metabolic byproducts may contribute to the pathogenesis of colonic inflammation and diarrhea. Future studies are warranted for the measurement of fecal concentrations of microbial and protozoal metabolites in cats with T. foetus infection for the identification of potential therapeutic targets.

Intestinal protozoan infections shape fecal bacterial microbiota in children from Guinea-Bissau.

Intestinal parasitic infections, caused by helminths and protozoa, are globally distributed and major causes of worldwide morbidity. The gut microbiota may modulate parasite virulence and host response upon infection. The complex interplay between parasites and the gut microbiota is poorly understood, partly due to sampling difficulties in remote areas with high parasite burden. In a large study of children in Guinea-Bissau, we found high prevalence of intestinal parasites. By sequencing of the 16S rRNA genes of fecal samples stored on filter paper from a total of 1,204 children, we demonstrate that the bacterial microbiota is not significantly altered by helminth infections, whereas it is shaped by the presence of both pathogenic and nonpathogenic protozoa, including Entamoeba (E.) spp. and Giardia (G.) lamblia. Within-sample diversity remains largely unaffected, whereas overall community composition is significantly affected by infection with both nonpathogenic E. coli (R2 = 0.0131, P = 0.0001) and Endolimax nana (R2 = 0.00902, P = 0.0001), and by pathogenic E. histolytica (R2 = 0.0164, P = 0.0001) and G. lamblia (R2 = 0.00676, P = 0.0001). Infections with multiple parasite species induces more pronounced shifts in microbiota community than mild ones. A total of 31 bacterial genera across all four major bacterial phyla were differentially abundant in protozoan infection as compared to noninfected individuals, including increased abundance of Prevotella, Campylobacter and two Clostridium clades, and decreased abundance of Collinsella, Lactobacillus, Ruminococcus, Veillonella and one Clostridium clade. In the present study, we demonstrate that the fecal bacterial microbiota is shaped by intestinal parasitic infection, with most pronounced associations for protozoan species. Our results provide insights into the interplay between the microbiota and intestinal parasites, which are valuable to understand infection biology and design further studies aimed at optimizing treatment strategies.

Interplay between Histomonas meleagridis and Bacteria: Mutualistic or Predator-Prey?

Histomonas meleagridis is an extracellular protozoan parasite and the aetiological agent of histomonosis, an important poultry disease whose impact is greatly accentuated by inaccessibility of any treatment. A special feature of the parasite is its intricate interplay with bacteria in vitro and in vivo, the focus of this article.

Some aspects of intracellular parasitism.

In intracellular parasitism the host cell is a true and hospitable host. The parasite does not have to break in the door. It has subtle ways of inducing the host to open the door and welcome it in. One of the exciting fields in the future of parasitology is to find out what these ways are and why they are sometimes so highly specific that the cell that invites one parasite in will not open the door to another closely related species. Once inside, the parasite not only exploits nutrients already available in the cell, and the cell's energy-yielding system, but it further induces the cell to assist actively in its nutrition. Like a bandit who has cajoled his way in, the parasite now forces his host to prepare a banquet for him. Finally it may destroy its host cell, as in most of the associations I have described herein, or it may stimulate its host cell to abnormal increase in size or to have an altered metabolism with the formation of new products. Or it may even contribute some positive benefit to the host cell or to the multicellular organism of which the cell is a part, so that the two kinds of organisms then live together in a state of mutualism or symbiosis (26).

Molecular Detection and Epidemiological Features of Selected Bacterial, Viral, and Parasitic Enteropathogens in Stool Specimens from Children with Acute Diarrhea in Thi-Qar Governorate, Iraq.

Knowledge of etiology causes of diarrheal illness is essential for development and implementation of public health measures to prevent and control this disease syndrome. There are few published studies examining diarrhea in children aged <5 years in Iraq. This study aims to investigate the occurrences and epidemiology of selected bacterial (Salmonella spp. and Campylobacter spp.), viral (adenovirus, norovirus GI and GII, and astrovirus), and parasitic (Entamoeba spp. and Giardia spp.) agents in stool samples from 155 child diarrheal cases enrolled between March and August 2017, in a hospital-based cross-sectional study in Thi-Qar, southeastern Iraq. Using molecular techniques and sequence-based characterization, adenovirus was the most frequently detected enteropathogen (53/155 (34.2%)), followed by Salmonella spp. (23/155 (14.8%)), Entamoeba spp. (21/155 (13.5%)), and Campylobacter spp. (17/155 (10.9%)). Mixed infection with Salmonella spp. and Campylobacter spp. was evident, and the same was revealed between various enteric viruses, particularly adenovirus and norovirus. The most frequent co-infection pattern was between adenovirus and Campylobacter spp., in seven cases (7/155 (4.5%)). Whole-genome sequencing-derived typing data for Salmonella isolates (n = 23) revealed that sequence type 49 was the most prevalent in this sample set (15/23 (65.2%)). To the best of our knowledge, this study provides the first report on detection and identification of floR, blaCARB-2, and mphA antimicrobial resistance genes in Salmonella isolated from children in the Middle East region. Logistic regression analysis pointed to few enteropathogen-specific correlations between child age, household water source, and breastfeeding patterns in relation to the outcome of detection of individual enteropathogens. This study presents the first published molecular investigation of multiple enteropathogens among children <5 years of age in Iraq. Our data provide supporting evidence for planning of childhood diarrhea management programs. It is important to build on this study and develop future longitudinal case-control research in order to elaborate the epidemiology of enteropathogens in childhood diarrhea in Iraq.

Pathologic and molecular characterization of histomoniasis in peafowl ( Pavo cristatus).

Histomonas meleagridis is a flagellate protozoan organism that can cause severe necrotizing typhlitis and hepatitis in gallinaceous birds. Peafowl ( Pavo spp.) have been shown to be susceptible to histomoniasis in experimental settings, but there are few reports of natural histomoniasis in this species. A retrospective study of the archived cases at 2 veterinary diagnostic laboratories in the United States yielded 5 cases of peafowl with gross and histologic findings characteristic of histomoniasis. Lesions included bilateral, transmural fibrinonecrotic typhlitis and multifocal necrotizing hepatitis with associated trophozoites morphologically consistent with H. meleagridis. There was no evidence of Heterakis gallinarum infestation in the studied cases. DNA was extracted from formalin-fixed, paraffin-embedded liver and ceca from all 5 cases and was analyzed using multiple sets of primers with subsequent sequencing and genotyping. Four samples were positive for H. meleagridis, and 1 sample was positive for both H. meleagridis and Tetratrichomonas gallinarum. These results confirm that peafowl develop clinical disease similar to that described previously in other gallinaceous birds infected by H. meleagridis. The role of T. gallinarum remains unknown and further research is necessary to elucidate its role, if any, in the pathogenesis of the observed lesions.

Human Intestinal Microbiota: Interaction Between Parasites and the Host Immune Response.

The human gut is a highly complex ecosystem with an extensive microbial community, and the influence of the intestinal microbiota reaches the entire host organism. For example, the microbiome regulates fat storage, stimulates or renews epithelial cells, and influences the development and maturation of the brain and the immune system. Intestinal microbes can protect against infection by pathogenic bacteria, viruses, fungi and parasites. Hence, the maintenance of homeostasis between the gut microbiota and the rest of the body is crucial for health, with dysbiosis affecting disease. This review focuses on intestinal protozoa, especially those still representing a public health problem in Mexico, and their interactions with the microbiome and the host. The decrease in prevalence of intestinal helminthes in humans left a vacant ecological niche that was quickly occupied by protozoa. Although the mechanisms governing the interaction between intestinal microbiota and protozoa are poorly understood, it is known that the composition of the intestinal bacterial populations modulates the progression of protozoan infection and the outcome of parasitic disease. Most reports on the complex interactions between intestinal bacteria, protozoa and the immune system emphasize the protective role of the microbiota against protozoan infection. Insights into such protection may facilitate the manipulation of microbiota components to prevent and treat intestinal protozoan infections. Here we discuss recent findings about the immunoregulatory effect of intestinal microbiota with regards to intestinal colonization by protozoa, focusing on infections by Entamoeba histolytica, Blastocystis spp, Giardia duodenalis, Toxoplasma gondii and Cryptosporidium parvum. The possible consequences of the microbiota on parasitic, allergic and autoimmune disorders are also considered.

Concentration effects of Winogradskyella sp. on the incidence and severity of amoebic gill disease.

To study the concentration effects of the bacterium Winogradskyella sp. on amoebic gill disease (AGD), Atlantic salmon Salmo salar were pre-exposed to 2 different doses (10(8) or 10(10) cells 1(-1)) of Winogradskyella sp. before being challenged with Neoparamoeba spp. Exposure of fish to Winogradskyella sp. caused a significant increase in the percentage of AGD-affected filaments compared with controls challenged with Neoparamoeba only; however, these percentages did not increase significantly with an increase in bacterial concentration. The results show that the presence of Winogradskyella sp. on salmonid gills can increase the severity of AGD.

Efficacy of ronidazole for treatment of feline Tritrichomonas foetus infection.

OBJECTIVES: To determine the efficacy of ronidazole (RDZ), tinidazole (TDZ), and metronidazole (MDZ) against Tritrichomonas foetus in vitro and of RDZ for treatment of feline naturally occurring or experimentally induced T. foetus infection. ANIMALS: A cat naturally infected with T. foetus infection and diarrhea. Ten specific-pathogen-free (SPF) kittens. PROCEDURE: RDZ, TDZ, and MDZ were tested for activity against 3 different feline isolates of T. foetus in vitro. RDZ then was administered to a naturally infected cat at 10 mg/kg PO q24h for 10 days. SPF kittens were infected orogastrically with feline T. foetus and treated with either placebo or RDZ (10 mg/kg PO q12h for 14 days). Cats with relapsing infection or those receiving placebo were treated subsequently with RDZ (either 30 or 50 mg/kg PO q12h for 14 days). Feces were examined for T. foetus by direct microscopy, culture, and polymerase chain reaction (PCR) testing weekly. RESULTS: Both RDZ and TDZ killed T. foetus at concentrations >0.1 microg/mL in vitro. In the naturally infected cat, RDZ abolished diarrhea and T. foetus infection for 85 days after treatment, at which time infection and diarrhea relapsed. Retreatment with RDZ eradicated diarrhea and T. foetus infection for over 407 days. In experimentally induced infection, RDZ at 10 mg/kg caused initial improvement, but infection relapsed in all 5 cats 2 to 20 weeks after treatment. At 30 or 50 mg/kg, 10/10 cats were negative for T. foetus infection for follow-up durations of 21 to 30 weeks after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of RDZ at 30 to 50 mg/kg q12h for 14 days resolved diarrhea and eradicated infection (on the basis of polymerase chain reaction [PCR] testing) in 1 naturally infected cat and 10 experimentally inoculated cats receiving a different isolate of T. foetus.

Microbiological risk factors in dentistry. Current status of knowledge.

Dentists belong to a professional group potentially exposed to harmful biological factors which most often are infectious microorganisms, less frequently - allergenic or toxic microorganisms. The fundamental routes of spreading harmful microorganisms in a dental surgery are: blood-borne, saliva-droplet, direct contact with a patient and with infected equipment, and water-droplet infections. In this paper, the current status of knowledge on microbiological hazards in a dentist's work is presented. Groups of microorganisms, such as prions, viruses, bacteria, fungi and protozoa, to which a dentist is, or may be exposed, are discussed. Epidemiological assessment of microbiological hazards in a dentist's work was performed and the basic principles of prevention formulated. Special attention was given to microflora in dental unit waterlines, and the biofilm persisting in them, as a source of occupational hazards specific for a dentist's workplace.

Bacterial, fungal and protozoan carbonic anhydrases as drug targets.

INTRODUCTION: The carbonic anhydrases (CAs, EC 4.2.1.1), a group of ubiquitously expressed metalloenzymes, are involved in numerous physiological and pathological processes, as well as in the growth and virulence of pathogens belonging to bacteria, fungi and protozoa. AREAS COVERED: CAs belonging to at least four genetic families, the α-, ß-, γ- and η-CAs, were discovered and characterized in many pathogens: i) Bacteria encode enzymes from one or more such families, which were investigated as potential drug targets. Inhibition of bacterial CAs by sulfonamides/phenol derivatives lead to inhibition of growth of the pathogen for Helicobacter pylori, Mycobacterium tuberculosis, Brucella suis; ii) Fungi encode for α- and ß-CAs, and inhibitors of the sulfonamide, thiol or dithiocarbamate type inhibited the growth of some of them (Malassezia globosa, Candida albicans, Crytpococcus neoformans, etc) in vivo; and iii) Protozoa encode α-, ß- or η-CAs. Sulfonamide, thiols and hydroxamates effectively killed such parasites (Trypanosoma cruzi, Leishmania donovani chagasi, Plasmodium falciparum) in vivo. EXPERT OPINION: None of the microorganism CAs is validated as drug targets as yet, but the inhibitors designed against many such enzymes showed interesting in vitro/in vivo results. By interfering with the activity of CAs from microorganisms, both pH homeostasis as well as crucial biosynthetic reactions are impaired, which lead to significant antiinfective effects, not yet exploited for obtaining pharmacological agents. As resistance to the clinically used antiinfectives is a serious healthcare problem worldwide, inhibition of parasite CAs may constitute an alternative approach for obtaining such agents with novel mechanisms of action.

Direct exposure to animal enteric pathogens.

Humans have very close interactions with working, food-producing, and companion animals. According to the American Veterinary Medical Association, there are more than one hundred million cat and dog pets in the United States. Furthermore, non-traditional pets like reptiles and exotic birds are not unusual companion animals in households. In addition to sharing with animals our living and/or working space and time, we also share, unfortunately, many disease causing microorganisms. In the past few years, we have become aware that several enteric pathogens that were thought to be mostly restricted to animals are a major cause of human disease. Examples of such pathogens include the protozoan parasite Cryptosporidium parvum and bacteria such as Campylobacter spp. This review will examine the characteristics of zoonotic enteric pathogens including bacterial (Helicobacter spp., Campylobacter spp., Salmonella spp., and verotoxin-producing Escherichia coli); parasitic (Toxoplasma gondii, Giardia spp., Cryptosporidium spp.); and viral (rotavirus, norwalk-like virus, hepatitis E virus), and the status of our knowledge with regard to the impact of such pathogens on human health.

Amphileptus branchiarum (Protozoa: Amphileptidae) in pond reared fish in Arkansas.

Amphileptus branchiarum is a protozoan parasite of fish in North America, Europe and Asia. In North America (Arkansas) it usually occurs on the gills of cyprinids from July to October. It seldom causes disease epizootics but may be responsible for epithelial hyperplasia and cell displacement in branchial tissue.

Distemper-like disease and encephalitozoonosis in wild dogs (Lycaon pictus).

Clinical signs of a fatal disease resembling those of canine distemper were observed in two groups of captive wild dog (Lycaon pictus) pups 13 days after vaccination with a commercially available combination vaccine for dogs which contained a live attenuated strain of canine distemper virus. Histopathological examination of tissues revealed the presence of intranuclear inclusion bodies in neurons and lesions resembling canine distemper as well as colonies of an Encephalitozoon sp. in the central nervous system and kidneys. Lesions were observed in both organs which resembled those described in other species infected with Encephalitozoon cuniculi.

Disseminated granulomas caused by an unidentified protozoan in sandhill cranes.

Oral granulomas were observed in 31 (33%) of 95 captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center. Necropsy of six of the afflicted cranes revealed granulomatous nodules throughout many of their organ systems. Intracellular protozoan organisms morphologically resembling schizogonic stages were observed within the granulomas by light and electron microscopy. Sexual and asexual stages of coccidia were seen in sections of the intestines of 4 of 5 cranes examined microscopically, and Eimerian oocysts were seen in fecal flotation specimens from 3 of 4 birds.

Infections with Encephalitozoon cuniculi and Leptospira interrogans, serovars grippotyphosa and ballum, in a kennel of foxhounds.

Leptospira interrogans serovars grippotyphosa and ballum were isolated from kidney and urine of an American Foxhound pup. The pup was from a litter of 12, all of which were unthrifty. Titers for serovar grippotyphosa in pups from the litter ranged from 200 to 6,400 and 23 of 36 adult dogs in the kennel had titers to that serovar. None of the sera was tested for antibodies to serovar ballum. Leptospires were not isolated from or observed in 2 littermates and 1 penmate, but gram-positive organisms morphologically compatible with Encephalitozoon cuniculi were detected in their brains and kidneys.

[The mechanisms of the pathogenicity of bacteria in different infections]. / Mekhanizmy patogennosti bakterii pri razlichnykh infektsiiakh.

The following ultrastructural formations are found in the bacteria of various infections: fibrillar and drop-like microcapsules, an increase of nucleotide size and number, micropyles. The dynamics of staphylococcus L-form formation in sepsis as well as the phenomenon of incomplete phagocytosis and endocytobiosis were studied. The latter is observed in mixed infection: dysentery bacteria lamblia, gonococci and trichomonas. These alterations indicate increased bacterial pathogenicity and seem to reflect the evolution of the bacteria adaptive mechanisms under the conditions of antibiotic therapy.

[Microsporidiosis and coccidiosis, protozoan diseases of flour beetles (Coleoptera, Tenebrionidae)]. / Mikrosporidioz i koktsidioz--protozoinye zabolevaniia malykh khrushchakov (Coleoptera, Tenebrionidae)

Tribolium destructor and T. confusum diseases caused by the fat body of the parasites Nosema whitei and Adelina tribolii were investigated. Life span and weight dynamics were examined at different temperatures and infection conditions. Infected females of T. confusum lay a less number of eggs. The gas produced by stink glands of T. destructor may inactivate the spores of N. whitei but does not affect those of A. tribolii.