Zoonotic Pathogens To Humans Research Articles

A framework for signaling throughout the life cycle of Babesia species.

Babesia species are tick-borne intracellular parasites that infect the red blood cells of their mammalian host, leading to severe or fatal disease. Babesia spp. infect a wide range of mammalian species and cause a significant economic burden globally, predominantly through disease in cattle. Several Babesia spp. are increasingly being recognized as zoonotic pathogens of humans. Babesia spp. have complex life cycles involving multiple stages in the tick and the mammalian host. The parasite utilizes complex signaling pathways during replication, egress, and invasion in each of these stages. They must also rapidly respond to their environment when switching between the mammalian and tick stages. This review will focus on the signaling pathways and environmental stimuli that Babesia spp. utilize in the bloodstream and for transmission to the tick, with an emphasis on the role of phosphorylation- and calcium-based signaling during egress and invasion. The expanding availability of in vitro and in vivo culture systems, genomes, transcriptomes, and transgenic systems available for a range of Babesia spp. should encourage further biological and translational studies of these ubiquitous parasites.

Campylobacter jejuni Cas9 Modulates the Transcriptome in Caco-2 Intestinal Epithelial Cells.

The zoonotic human pathogen Campylobacter jejuni is known for its ability to induce DNA-damage and cell death pathology in humans. The molecular mechanism behind this phenomenon involves nuclear translocation by Cas9, a nuclease in C. jejuni (CjeCas9) that is the molecular marker of the Type II CRISPR-Cas system. However, it is unknown via which cellular pathways CjeCas9 drives human intestinal epithelial cells into cell death. Here, we show that CjeCas9 released by C. jejuni during the infection of Caco-2 human intestinal epithelial cells directly modulates Caco-2 transcriptomes during the first four hours of infection. Specifically, our results reveal that CjeCas9 activates DNA damage (p53, ATM (Ataxia Telangiectasia Mutated Protein)), pro-inflammatory (NF-κB (Nuclear factor-κB)) signaling and cell death pathways, driving Caco-2 cells infected by wild-type C. jejuni, but not when infected by a cas9 deletion mutant, towards programmed cell death. This work corroborates our previous finding that CjeCas9 is cytotoxic and highlights on a RNA level the basal cellular pathways that are modulated.

Detection of zoonotic human pathogens from Ixodes scapularis in Wisconsin.

Detection of zoonotic human pathogens from Ixodes scapularis in Wisconsin.

Conservation of Rhodococcus equi (Magnusson 1923) Goodfellow and Alderson 1977 and rejection of Rhodococcus hoagii (Morse 1912) Kämpfer et al. 2014.

A recent taxonomic study confirmed the synonymy of Rhodococcus equi (Magnusson 1923) Goodfellow and Alderson 1977 and Corynebacterium hoagii (Morse 1912) Eberson 1918. As a result, both R. equi and C. hoagii were reclassified as Rhodococcus hoagii comb. nov. in application of the principle of priority of the Prokaryotic Code. Because R. equi is a well-known animal and zoonotic human pathogen, and a bacterial name solidly established in the veterinary and medical literature, we and others argued that the nomenclatural change may cause error and confusion and be potentially perilous. We have now additionally found that the nomenclatural type of the basonym C. hoagii , ATCC 7005T, does not correspond with the original description of the species C. hoagii in the early literature. Its inclusion as the C. hoagii type on the Approved Lists 1980 results in a change in the characters of the taxon and in C. hoagii designating two different bacteria. Moreover, ATCC 7005, the only strain in circulation under the name C. hoagii , does not have a well documented history; it is unclear why it was deposited as C. hoagii and a possible mix-up with a Corynebacterium ( Rhodococcus ) equi isolate is a reasonable assumption. We therefore request the rejection of Rhodococcus hoagii as a nomen ambiguum, nomen dubium and nomen perplexum in addition to nomen periculosum, and conservation of the name Rhodococcus equi , according to Rules 56ab of the Code.

Epidemiological serosurvey of vector-borne and zoonotic pathogens among homeless people living in shelters in Marseille: cross-sectional one-day surveys (2005-2015).

Homeless people are often exposed to unhygienic environments as well as to animals carrying arthropods which both transmit zoonotic infections and human louse-borne pathogens. We attempted to determine the prevalence of antibodies against several vector-borne and zoonotic pathogens among homeless adults living in Marseille. During the 2005-2015 period, we collected sera samples from 821 homeless adults living in shelters. Antibodies against Bartonella quintana, Bartonella henselae, Borrelia recurrentis, Coxiella burnetii, Francisella tularensis (with a cut-off of 1:100), Rickettsia akari, Rickettsia conorii, Rickettsia felis, Rickettsia prowazekii, and Rickettsia typhi (with a cut-off of 1:64) were searched by microimmunofluorescence (MIF). MIF-positive serum samples were confirmed by cross-adsorption to characterise cross-reacting antigens and immunoblotting. Positive sera by Western blot were further tested using qPCR. We evidenced a prevalence of 4.9% seroreactivity to at least one pathogen including phase II C. burnetii (2.1%), B. quintana (1.7%), R. conorii (0.4%), R. prowazekii (0.4%), R. typhi (0.1%), B. recurrentis (0.1%), and F. tularensis (0.1%). No DNA from any pathogens was detected. A comparison with studies conducted prior to the 2000-2003 period showed a decrease in the overall seroprevalence of several vector-borne and zoonotic infections.

Fatal case of bacteremia caused by Streptococcus suis in a splenectomized man and a review of the European literature

Streptococcus suis is an emerging zoonotic human pathogen, which is a causative agent of invasive infections in people who are in close contact with infected pigs or contaminated pork products. It is associated with severe systemic infections, most commonly meningitis and sepsis, which may lead to high rates of morbidity and mortality. Serotype 2 is the most prevalent type in S. suis infections in humans. We have reported a case of a very rapidly proceeding fatal human S. suis infection in a splenectomized, but otherwise immunocompetent patient in Hungary. We would like to highlight the attention for this pathogen for the risk group patients, not only pig breeders, veterinarians, abattoir workers, meat processing and transport workers, butchers and cooks, that those persons who are immunocompromised including those with spleen removed, persons with diabetes mellitus, cancer and alcoholism, are also at greater risk of infection.

Characterization of Pasteurella multocida isolates from rabbits in China

Pasteurella multocida is the causative agent of a wide range of diseases (pasteurellosis) and is a zoonotic pathogen in humans. The molecular epidemiology of P. multocida from rabbits in some southern European countries has been characterized, and the associations of some populations with the respiratory niche or virulence factors have been suggested. However, the population structure of P. multocida from rabbits in China has not been well characterized. In this study, 30 P. multocida isolates from rabbits without epidemiological relations in China were clustered using mutilocus sequence typing (MLST). Then, the genotypes of virulence factors (capsule, lipopolysaccharides, HgbB, and PfhA) of these isolates were determined via multiplex PCR methods. Next, the virulence of the isolates in a mice model was established by determining the 50 % lethal dose. Finally, the associations between MLST types and the prevalence of genotypes, virulent strains, or clinical origins were characterized. The P. multocida isolates identified in this work included 3 major clonal complexes: CC9, CC74, and ST129. CC9 exhibited cpsA(F)L3, and was associated with a higher prevalence of rhinitis; CC74 exhibited cpsAL6, and was associated with higher prevalences of hgbB+pfhA- and pneumonia; ST129 exhibited cpsAL1, and was associated with higher prevalences of high-virulence strains and septicemia. The results provided insights into P. multocida from rabbits in China and suggested the use of strains from different populations in future P. multocida pathogenesis and vaccine studies.

Instability of Nucleic Acids in Airborne Microorganisms under Far Infrared Radiation

Emergence of zoonotic-human pathogens is proven to be a lethal threat to public health, and RNA virus including influenza viruses, severe acute respiratory syndrome coronavirus, middle east respiratory syndrome coronavirus, and COVID-19, plays a pivotal role. As those viruses as airborne microorganisms spread mainly by tiny airborne particles, it is important to de-active those airborne particles before their entry into human bodies. In this study, we investigated the effect of far infrared (FIR) radiation on inhibition of airborne microorganisms. The result confirmed that double stand DNA from airborne microorganisms containing RNA viruses was stable under mild FIR radiation. However, single strand RNA from them was found to be sensitive to FIR radiation, indicating that RNA virus in airborne particles is instable under FIR radiation. Based on this observation, two models on usage of FIR radiation to prevent RNA virus transmission by air and cure RNA virus infection were proposed. Then, this study suggests that FIR radiation has the potential to be a cheap, convenient, and efficient method in clinic to treat RNA virus.

Functional analysis of hisJ in Aeromonas veronii reveals a key role in virulence.

Aeromonas veronii is an important aquatic zoonotic pathogen in humans and animals. In recent years, extracellular proteins from bacteria have been found to be the major pathogenic factors for aquatic animals. The aim of this study was to systematically analyze the extracellular proteins of nine sources of A. veronii and the effects of hisJ on virulence. We screened only the common proteins from nine different sources of A. veronii by liquid chromatography-tandem mass spectrometry and identified the gene hisJ. We then constructed ΔhisJ (deleted) and C-hisJ (complemented) variants of A. veronii TH0426 to assess the biological function of hisJ. While the ΔhisJ strain did not show altered growth (P > 0.05), we observed that it had reduced colony formation and biofilm formation and reduced adhesion to and invasion of epithelioma papulosum cyprini cells by 2.0-, 1.9-, and 10.8-fold, respectively. Additionally, infection experiments on zebrafish and mouse infection experiments showed that the virulence of the ΔhisJ strain was decreased by 865-fold (P < 0.001) compared with the wild-type strain; virulence of the complemented C-hisJ strain was reduced only 2.8-fold. Furthermore, in the context of hisJ deletion, flagella of A. veronii TH0426 were easily detached and the expression of virulence genes was downregulated. A persistence test (of bacterial colonies in crucian carp) showed that the number of bacteria in the immune organs of the ΔhisJ-infected group was lower than that in the wild-type-infected group. Overall, these results show that hisJ affects flagellar shedding, virulence, biofilm formation, adhesion, and invasion of A. veronii TH0426, and that hisJ is closely associated with virulence and plays a crucial role in its pathogenicity of A. veronii TH0426.

Molecular techniques for the detection of bacterial zoonotic pathogens in fish and humans

Various diseases could be transmitted from aquatic species, especially fish, to humans, which is considered to be a major human health concern across the world. In recent decades, molecular techniques have been applied to examine and identify various bacterial species in fish farms. Molecular techniques are rapid, accurate, sensitive, cost-effective, and have the ability to identify specific pathogens without the need for conventional methods. Furthermore, molecular techniques are particularly useful for the detection of multiple species or in case of low template. This review study aimed to describe various molecular methods, including multiplex-polymerase chain reaction, high-resolution melting real-time, restriction fragment length polymorphism, random amplification of polymorphic DNA, nucleic acid sequence-based amplification, rolling circle amplification, fluorescence in-situ hybridization, microarray, and matrix-assisted laser desorption/ionization. In addition, we evaluated the biosensors used for the detection of zoonotic bacteria, such as Vibrio vulnificus, Vibrio cholerae, Listeria monocytogenes, Streptococcus iniae, Lactococcus garvieae, Aeromonas hydrophila, Edwardsiella tarda, Mycobacterium spp., Photobacterium damselae subsp. Damselae, and Pseudomonas fluorescens, which are transmitted from fish to humans. These bacteria are of great importance in the aquaculture industry and in terms of human health.

A Zoonotic Adenoviral Human Pathogen Emerged through Genomic Recombination among Human and Nonhuman Simian Hosts.

Genomics analysis of a historically intriguing and predicted emergent human adenovirus (HAdV) pathogen, which caused pneumonia and death, provides insight into a novel molecular evolution pathway involving "ping-pong" zoonosis and anthroponosis. The genome of this promiscuous pathogen is embedded with evidence of unprecedented multiple, multidirectional, stable, and reciprocal cross-species infections of hosts from three species (human, chimpanzee, and bonobo). This recombinant genome, typed as HAdV-B76, is identical to two recently reported simian AdV (SAdV) genomes isolated from chimpanzees and bonobos. Additionally, the presence of a critical adenoviral replication element found in HAdV genomes, in addition to genes that are highly similar to counterparts in other HAdVs, reinforces its potential as a human pathogen. Reservoirs in nonhuman hosts may explain periods of apparent absence and then reemergence of human adenoviral pathogens, as well as present pathways for the genesis of those thought to be newly emergent. The nature of the HAdV-D76 genome has implications for the use of SAdVs as gene delivery vectors in human gene therapy and vaccines, selected to avoid preexisting and potentially fatal host immune responses to HAdV.IMPORTANCE An emergent adenoviral human pathogen, HAdV-B76, associated with a fatality in 1965, shows a remarkable degree of genome identity with two recently isolated simian adenoviruses that contain cross-species genome recombination events from three hosts: human, chimpanzee, and bonobo. Zoonosis (nonhuman-to-human transmission) and anthroponosis (human to nonhuman transmission) may play significant roles in the emergence of human adenoviral pathogens.

Comparative analysis reveals conservation in genome organization among intestinal Cryptosporidium species and sequence divergence in potential secreted pathogenesis determinants among major human-infecting species

BackgroundCryptosporidiosis is a major cause of gastrointestinal diseases in humans and other vertebrates. Previous analyses of invasion-related proteins revealed that Cryptosporidium parvum, Cryptosporidium hominis, and Cryptosporidium ubiquitum mainly differed in copy numbers of secreted MEDLE proteins and insulinase-like proteases and sequences of mucin-type glycoproteins. Recently, Cryptosporidium chipmunk genotype I was identified as a novel zoonotic pathogen in humans. In this study, we sequenced its genome and conducted a comparative genomic analysis.ResultsThe genome of Cryptosporidium chipmunk genotype I has gene content and organization similar to C. parvum and other intestinal Cryptosporidium species sequenced to date. A total of 3783 putative protein-encoding genes were identified in the genome, 3525 of which are shared by Cryptosporidium chipmunk genotype I and three major human-pathogenic Cryptosporidium species, C. parvum, C. hominis, and Cryptosporidium meleagridis. The metabolic pathways are almost identical among these four Cryptosporidium species. Compared with C. parvum, a major reduction in gene content in Cryptosporidium chipmunk genotype I is in the number of telomeric genes encoding MEDLE proteins (two instead of six) and insulinase-like proteases (one instead of two). Highly polymorphic genes between the two species are mostly subtelomeric ones encoding secretory proteins, most of which have higher dN/dS ratios and half are members of multiple gene families. In particular, two subtelomeric ABC transporters are under strong positive selection.ConclusionsCryptosporidium chipmunk genotype I possesses genome organization, gene content, metabolic pathways and invasion-related proteins similar to the common human-pathogenic Cryptosporidium species, reaffirming its human-pathogenic nature. The loss of some subtelomeric genes encoding insulinase-like proteases and secreted MEDLE proteins and high sequence divergence in secreted pathogenesis determinants could contribute to the biological differences among human-pathogenic Cryptosporidium species.

Characterization of host plasminogen exploitation of Pasteurella multocida

Pasteurella multocida is the causative agent of a wide range of disease (pasteurellosis) and a zoonotic pathogen in humans. Some pathogenic bacteria are able to exploit host plasminogen for migration across tissue barriers or evade from host innate immunity. However, there is no study on host plasminogen exploitation of P. multocida. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) has been reported to be a plasminogen receptor in many pathogenic bacteria, but its role in P. multocida exploiting plasminogen has not yet been characterized. The aim of this study was to detect the activity of P. multocida to exploit host plasminogen and evaluate the ability of GAPDH to act as a receptor in the recruitment process. P. multocida could recruit host plasminogen and exhibited plasmin activity when stimulated by urokinase. GAPDH exhibited binding activity to plasminogen. GAPDH Antiserum significantly decrease the plasminogen recruitment activity of P. multocida. In conclusion, P. multocida is able to exploit host plasminogen via GAPDH. To our knowledge, this is the first report on host plasminogen exploitation of P. multocida.

Combination of microbiome analysis and serodiagnostics to assess the risk of pathogen transmission by ticks to humans and animals in central Germany

BackgroundArthropod-borne diseases remain a major health-threat for humans and animals worldwide. To estimate the distribution of pathogenic agents and especially Bartonella spp., we conducted tick microbiome analysis and determination of the infection status of wild animals, pets and pet owners in the state of Hesse, Germany.ResultsIn total, 189 engorged ticks collected from 163 animals were tested. Selected ticks were analyzed by next generation sequencing (NGS) and confirmatory PCRs, blood specimens of 48 wild animals were analyzed by PCR to confirm pathogen presence and sera of 54 dogs, one cat and 11 dog owners were analyzed by serology. Bartonella spp. were detected in 9.5% of all ticks and in the blood of 17 roe deer. Further data reveal the presence of the human and animal pathogenic species of genera in the family Spirochaetaceae (including Borrelia miyamotoi and Borrelia garinii), Bartonella spp. (mainly Bartonella schoenbuchensis), Rickettsia helvetica, Francisella tularensis and Anaplasma phagocytophilum in ticks. Co-infections with species of several genera were detected in nine ticks. One dog and five dog owners were seropositive for anti-Bartonella henselae-antibodies and one dog had antibodies against Rickettsia conorii.ConclusionsThis study provides a snapshot of pathogens circulating in ticks in central Germany. A broad range of tick-borne pathogens are present in ticks, and especially in wild animals, with possible implications for animal and human health. However, a low incidence of Bartonella spp., especially Bartonella henselae, was detected. The high number of various detected pathogens suggests that ticks might serve as an excellent sentinel to detect and monitor zoonotic human pathogens.

Starry Heart Valve: A Story Behind CAT Scratch

SESSION TITLE: Bacterial Infections 1 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Bartonella species are zoonotic bacterial pathogens in humans. B.quintana and B.henselae are the most common agents causing human infections. B.henselae infection is associated with exposure to cats and their fleas; endocarditis may occur in patients with known valvular disease. CASE PRESENTATION: A 62-year-old female, with no prior history of heart disease, presented with 10 days of bilateral leg swelling, malaise and exertional dyspnea. She lived with her 4 cats. Examination was notable for bilateral pitting edema extending to her waist with visible scratch marks on her abdomen and lower extremities. Laboratory data revealed new pancytopenia and an elevated serum creatinine (2.1 mg/dl). She was started on clindamycin for cellulitis. Blood cultures were negative. Transthoracic echocardiogram, obtained to evaluate the severe edema, showed an aortic valve vegetation measuring 2.7 cm x 1.3 cm with aortic insufficiency. The lesion was confirmed with a transesophageal study. The patient was deemed to have culture negative endocarditis; antibiotics were changed to vancomycin, ceftriaxone and doxycycline. B.henselae and B.quintana IgG titers were positive with the titer of > 1:1024. She underwent an aortic valve replacement. PCR of the heart valve tissue was positive for Bartonella. The bacterial colonies were strongly positive by Warthin Starry stain and demonstrated strong reactivity with a Bartonella immunostain. Vancomycin and ceftriaxone were discontinued; she was transitioned to doxycycline 100 mg twice daily with rifampin 300 mg twice daily for six weeks followed by doxycycline monotherapy for 6 months. DISCUSSION: Patients with Bartonella endocarditis generally present with subacute, nonspecific symptoms including fever, fatigue, weakness, and weight loss, like our patient. Our patient’s exposure to her four cats, with frequent scratches on her thighs and lower abdomen, and a culture-negative valuvular vegetation, raised the suspicion of Bartonella endocarditis. There are several methods to confirm the presence of Bartonella infection including tissue cell culture, Warthin-Starry staining of the resected valve, immuno histologic methods, serologic testing, and PCR amplification using valve specimens. If Bartonella is proven, treatment with 6 weeks of doxycycline along with 2 weeks of gentamycin and rifampin is recommended. However, there are no set guidelines defining optimal duration of therapy. Anecdotal evidences support extended doxycycline therapy for 3-6 months to prevent potential dissemination. CONCLUSIONS: Clinicians should suspect Bartonella endocarditis in patients with culture-negative endocarditis who have had extensive contact to cats. Reference #1: Chomel B et al: Fatal Case of Endocarditis Associated with Bartonella henselae Type I Infection in a Domestic Cat. Journal Of Clinical Microbiology; Nov. 2003, p. 5337-5339 Reference #2: Drancourt M et al: Bartonella (rochalimaea) quintana endocarditis in three homeless men. N Engl J Med 1995;332: 419-23 DISCLOSURE: The following authors have nothing to disclose: Thushara Paul, Siddhant Datta No Product/Research Disclosure Information

Associations between animal welfare indicators and Campylobacter spp. in broiler chickens under commercial settings: A case study

Few studies have previously investigated how poor animal welfare might be associated with infection of zoonotic pathogens in humans. This paper assesses the predictive value of the presence of Campylobacter spp. in broiler chicken flocks when animal-based measures related to footpad dermatitis, hock burns, body lesions and arthritis are identified under commercial conditions (high density). The study population included 32 flocks analysed on farm and at slaughter, slaughtered between April and August 2008 in six different slaughter plants in Brittany, France. Welfare and health indicators are those indicated by the European legislation and sampling was carried out in the framework of the European baseline survey on the prevalence of Campylobacter in broiler chicken. Caecal contents, sampled both on farm and at slaughter, and carcass skin samples from the neck and breast at slaughter, were investigated for the presence of Campylobacter spp. Logistic models/classification trees were used to estimate the probability of the presence (or absence) of a specific foodborne pathogen in a flock based on specific animal-based measures (or combinations of measures) in order to study the potential relationship between welfare indicators and foodborne pathogen prevalence/incidence levels. On farm, flocks with more than 25% animals with severe lesions on between 25 and 50% of the footpad are predicted to be Campylobacter-positive whereas flocks where less than 13 individuals have arthritis are predicted to be Campylobacter-negative. The error rate on farm and at slaughter was 10 and 4% respectively indicating good predicting abilities. A poor welfare environment may result in stress, which reduces chicken immunocompetence making them more susceptible to Campylobacter spp. An infection with Campylobacter spp may lead to impaired defence and susceptibility to other pathogens which may result in greater intestinal excretion. Poor welfare and high growing rate lead to digestive troubles that lead to litter humidity. Litter humidity that, among other things, causes footpad dermatitis may also influence the horizontal transmission of the Campylobacter spp. infection due to the normal coprophagic behaviour of poultry. Reducing welfare problems by a better management of rearing conditions would not only improve broiler welfare, but it would also decrease the risks of Campylobacter contamination, of carcass condemnations and of economic loss for the poultry industry.

Impact of a Food Safety Campaign on Streptococcus suis Infection in Humans in Thailand.

AbstractStreptococcus suis is an important zoonotic pathogen in swine and humans that causes sepsis and meningitis. Our previous study in Thailand showed that the prevalence of S. suis infection in humans, especially in northern areas of Thailand, and the transmission of the pathogen occurred mainly through the consumption of traditional raw pork products. Considering the high incidence proportion and mortality rate of the disease as an important public health problem, we implemented a food safety campaign in the Phayao Province in northern Thailand in 2011. We evaluated the effects of a food safety campaign by comparing the sociodemographic, clinical, and bacteriological characteristics of cases before and after the campaign. The follow-up study showed a marked decrease of the incidence proportion in the first 2 years, indicating the effectiveness of the campaign. In the third year, however, the incidence proportion slightly increased again, indicating the existence of deep-rooted cultural behaviors and the necessity of continuous public health intervention. Furthermore, epidemiological analysis of the cases made it possible to estimate the infectivity of the pathogen via the oral route of infection. In the present study, we showed the effectiveness of the food safety campaign for controlling the S. suis infection, and we present a role model public health intervention for prevalent areas affected by S. suis infection in humans.

Occurrence of Coxiella burnetii, Ehrlichia canis, Rickettsia species and Anaplasma phagocytophilum-like bacterium in ticks collected from dogs and cats in South Africa.

Ticks are major vectors of arthropod-borne infections and transmit a wide variety of zoonotic pathogens. This study was conducted mainly to determine the occurrence of canine tick-borne bacterial and rickettsial pathogens especially those with zoonotic potential. We examined 276 Rhipicephalus sanguineus, 38 Haemaphysalis elliptica and 4 Amblyomma hebraeum ticks from 90 dogs and 4 cats from the Free State, KwaZulu-Natal, North West and Mpumalanga provinces. DNA of Coxiella burnetii (41%), Ehrlichia or Anaplasma (18%), Rickettsia spp. (37%), Anaplasma phagocytophilum-like bacterium (18%) and Ehrlichia canis (19%) was detected by polymerase chain reaction (PCR) from a total of 147 pooled DNA samples. All samples were negative for the presence of Borrelia burgdorferi DNA. Ehrlichia canis was detected in samples from all the provinces except the North West; A. phagocytophilum was absent in KwaZulu-Natal samples, whereas Rickettsia species and C. burnetii were detected in all sampled provinces. The PCR-positive samples were confirmed by direct sequencing of the product. Data from this study calls for a joint effort by both veterinary and medical sectors to conduct epidemiological studies of the zoonotic pathogens in both animals and humans.

EGFR transactivation contributes to neuroinflammation in Streptococcus suis meningitis.

Background Streptococcus suis serotype 2 (SS2) is an important zoonotic bacterial pathogen in both humans and animals, which can cause high morbidity and mortality. Meningitis is one of the major clinical manifestations of SS2 infection. However, the specific process of SS2 meningitis and its molecular mechanisms remain unclear. Epidermal growth factor receptor (EGFR) has been reported to initiate transduction of intracellular signals and regulate host inflammatory responses. Whether and how EGFR contributes to the development of S. suis meningitis are currently unknown.MethodsThe tyrosine phosphorylation of cellular proteins, the transactivation of EGFR, as well as its dimerization, and the associated signal transduction pathways were investigated by immunoprecipitation and western blotting. Real-time quantitative PCR was used to investigate the transcriptional level of the ErbB family members, EGFR-related ligands, cytokines, and chemokines. The secretion of cytokines and chemokines in the serum and brain were detected by Q-Plex™ Chemiluminescent ELISA.ResultsWe found an important role of EGFR in SS2 strain SC19-induced meningitis. SC19 increasingly adhered to human brain microvascular endothelial cells (hBMEC) and caused inflammatory lesions in the brain tissues, with significant induction and secretion of proinflammatory cytokines and chemokines in the serum and brains. SC19 infection of hBMEC induced tyrosine phosphorylation of cellular EGFR in a ligand-dependent manner involving the EGF-like ligand HB-EGF, amphiregulin (AREG), and epiregulin (EREG) and led to heterodimerization of EGFR/ErbB3. The EGFR transactivation did not participate in SS2 strain SC19 adhesion of hBMEC, as well as in bacterial colonization in vivo. However, its transactivation contributed to the bacterial-induced neuroinflammation, via triggering the MAPK-ERK1/2 and NF-κB signaling pathways in hBMEC that promote the production of proinflammatory cytokines and chemokines.ConclusionsWe investigated for the first time the tyrosine phosphorylation of cellular proteins in response to SS2 strain SC19 infection of hBMEC and demonstrated the contribution of EGFR to SS2-induced neuroinflammation. These observations propose a novel mechanism involving EGFR in SS2-mediated inflammatory responses in the brain, and therefore, EGFR might be an important host target for further investigation and prevention of neuroinflammation caused by SS2 strains.

Development of a multilocus sequence typing tool for high-resolution subtyping and genetic structure characterization of Cryptosporidium ubiquitum

Cryptosporidium ubiquitum is an emerging zoonotic pathogen in humans. Recently, a subtyping tool targeting the 60-kDa glycoprotein (gp60) gene was developed for C. ubiquitum, and identified six subtype families (XIIa-XIIf). In this study, we selected five genetic loci known to be polymorphic in C. hominis and C. parvum for the development of a multilocus subtyping tool for C. ubiquitum, including CP47 (cgd6_1590), MSC6-5 (cgd6_4290), cgd6_60, cgd2_3690, and cgd4_370. PCR primers for these targets were designed based on whole genome sequence data from C. ubiquitum. DNA sequence analyses of 24 C. ubiquitum specimens showed the presence of 18, 1, 5, 4, and 5 subtypes at the CP47, MSC6-5, cgd6_60, cgd2_3690, and cgd4_370 loci, respectively. Altogether, 18 multilocus sequence typing (MLST) subtypes were detected among the 19 specimens successfully sequenced at all polymorphic loci. Phylogenetic analyses of the MLST data indicated that the rodent subtype families of XIIe and XIIf were highly divergent from others, and the ruminant XIIa subtype family formed a monophyletic group genetically distant from other rodent subtype families XIIb, XIIc, and XIId. The latter showed no consistent grouping of specimens and formed one large cluster in phylogenetic analysis of concatenated multilocus sequences. This was supported by results of STRUCTURE and FST analyses, which further suggested that XIIa originated from one common ancestor whereas XIIb, XIIc, and XIId contained mixed ancestral types, reflecting a close relatedness of the three subtype families and the likely occurrence of genetic recombination among them. Thus, an MLST tool was developed for high-resolution subtyping of C. ubiquitum and results of preliminary characterizations of specimens from humans and animals supported the conclusion on the existence of ruminant and rodent-adapted C. ubiquitum groups.