When do co-infections matter?

A Cell for the Ages: Human γδ T Cells across the Lifespan

The complexity of the human immune system is exacerbated by age-related changes to immune cell functionality. Many of these age-related effects remain undescribed or driven by mechanisms that are poorly understood. γδ T cells, while considered an adaptive subset based on immunological ontogeny, retain both innate-like and adaptive-like characteristics. This T cell population is small but mighty, and has been implicated in both homeostatic and disease-induced immunity within tissues and throughout the periphery. In this review, we outline what is known about the effect of age on human peripheral γδ T cells, and call attention to areas of the field where further research is needed.

Opportunist Coinfections by Nontuberculous Mycobacteria and Fungi in Immunocompromised Patients

Nontuberculous mycobacteria (NTM) and many fungal species (spp.) are commonly associated with opportunistic infections (OPIs) in immunocompromised individuals. Moreover, occurrence of concomitant infection by NTM (mainly spp. of Mycobacterium avium complex and Mycobacterium abscessus complex) and fungal spp. (mainly, Aspergillus fumigatus, Histoplasma capsulatum and Cryptococcus neoformans) is very challenging and is associated with poor patient prognosis. The most frequent clinical symptoms for coinfection and infection by single agents (fungi or NTM) are similar. For this reason, the accurate identification of the aetiological agent(s) is crucial to select the best treatment approach. Despite the significance of this topic it has not been sufficiently addressed in the literature. This review aims at summarizing case reports and studies on NTM and fungi coinfection during the last 20 years. In addition, it briefly characterizes OPIs and coinfection, describes key features of opportunistic pathogens (e.g., NTM and fungi) and human host predisposing conditions to OPIs onset and outcome. The review could interest a wide spectrum of audiences, including medical doctors and scientists, to improve awareness of these infections, leading to early identification in clinical settings and increasing research in the field. Improved diagnosis and availability of therapeutic options might contribute to improve the prognosis of patients' survival.

Concurrent infection of intestinal parasites and Helicobacter pylori among school-age children in Central Ethiopia

Background

Coinfection of multiple intestinal microbial pathogens plays an important role in individuals harboring these organisms. However, data on magnitude and risk factors are scarce from resource limited settings.

Objective

We examined the prevalence and associated risk factors of intestinal parasites and Helicobacter pylori co-infection among young Ethiopian school children.

Method

Data from a total of 434 Ethiopian school children from the Ziway region were analyzed in the study. Stool antigen and blood serum antibody tests were used to detect H. pylori, while the presence of any intestinal parasites was detected using direct wet mount microscopy and formol-ether concentration techniques. A structured questionnaire was delivered to mothers and legal guardians of the children by an interviewer to collect data relevant demographic and lifestyle factors. Multivariate logistic regression analysis was performed to assess the association of these sociodemographic characteristics with the coinfection of H. pylori and intestinal parasites.

Results

The prevalence of coinfection with any intestinal parasites and Helicobacter pylori was 23.0% (n = 92/400). Univariate analysis showed an increased risk for co-infection among children whose mothers had non-formal education (COR: 1.917, p < 0.01) and those who had no history of child vaccination (COR: 3.455, p = 0.084). Children aged 10–14 and those who lived in a house that had a flush or ventilated latrine were found at lower odds of coinfection between intestinal parasites and Helicobacter pylori (COR: 0.670, p = 0.382; COR: 0.189, p = 0.108). Multivariate regression analysis showed increased odds of co-infection among children whose mothers had non-formal education (AOR: 1.978, p < 0.01). Maternal education was also associated with a two-fold increase in odds for H. pylori and any protozoa co-infection (AOR: 2.047, p < 0.01).

Conclusion

Our study shows a moderate prevalence of H. pylori and intestinal parasite co-infection and identified maternal education as a significant risk factor among school children.

Kaposi's sarcoma-associated herpesvirus related malignancy in India, a rare but emerging member to be considered

Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with viral malignancy, related to HIV-AIDS. With a wide geographical discrimination in its occurrence, Asian countries shows low to moderate prevalence with higher occurrence in some particular areas. India is one of the largest countries in Asia, having various geographical and cultural variations where KSHV has been considered as an unthinkable entity to cause any of its associated disease. India has been reported as a low prevalent zone for KSHV malignancy till date. Also there are no reports so far, describing the occurrence pattern of this malignancy. So this review approaches towards figuring out the tendency of prevalence pattern of this malignancy and associated risk factors found to be present in Indian population. From this study it is revealed that, KSHV related malignancy is a relatively newly reported and emerging disease in India and may exist in hidden pockets throughout India in association with tuberculosis. India shows prevalence in HIV-associated Kaposi's sarcoma in regions where socially discriminated LGBT (lesbian, gay, bisexual, and transgender) groups, unprotected sexual behavior and heterosexuality are the important risk factors for sexually transmitted viral diseases. Anti-retro viral therapy is not sufficient to combat the virus and may act adversely. On a note regarding the clinical representations of Kaposi's sarcoma, oral, mucosal, pleural and abdominal involvements are observed in worst cases and these can be considered as the main manifesting criteria for this malignancy among Indians.

Accuracy and Cross-Reactivity of Rapid Diagnostic Tests for Norovirus and Rotavirus in a Real Clinical Setting

Background

Rapid diagnostic test (RDT) of norovirus and rotavirus is commonly used for outbreak screening and patient management. Varying accuracy of the test and cross-reactivity has been reported and could affect the outcome of management. The primary purpose of this study is to provide the accuracy of norovirus and rotavirus rapid diagnostic tests and to analyze the cross-reactivity of both tests.

Materials and Methods

Stool samples collected from every acute diarrhea patient aged <15 years old who was admitted at Bhumibol Adulyadej Hospital, Bangkok, Thailand, from November 2014 to September 2016 underwent the following test: QuickNaviTM – Norovirus2 for norovirus, VIKIA^® Rota-Adeno for rotavirus, and aerobic bacterial culture. Real-time reverse transcription polymerase chain reaction was used as a gold standard for virus detection. False-positive results determined cross-reactivity.

Results

From 358 stool specimens, the sensitivity of RDTs for norovirus and rotavirus was 27.5% and 44.8%, respectively. The specificity of RDTs for norovirus and rotavirus was 97.7% and 91.6%, respectively. False positive results of RDT for norovirus occurred in 6 samples (1.7%) and 22 samples (6.1%) in RDT for rotavirus. Rotavirus RDT was found to have cross-reactivity with 11 norovirus infection and 3 bacterial infected stools.

Conclusion

We found that the RDTs for both rotavirus and norovirus have high specificity but low sensitivity. Cross-reactivity was observed in positive rotavirus RDT with half of it being norovirus.

Bacterial co-infections with SARS-CoV-2

The pandemic coronavirus disease 2019 (COVID‐19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2), has affected millions of people worldwide. To date, there are no proven effective therapies for this virus. Efforts made to develop antiviral strategies for the treatment of COVID‐19 are underway. Respiratory viral infections, such as influenza, predispose patients to co‐infections and these lead to increased disease severity and mortality. Numerous types of antibiotics such as azithromycin have been employed for the prevention and treatment of bacterial co‐infection and secondary bacterial infections in patients with a viral respiratory infection (e.g., SARS‐CoV‐2). Although antibiotics do not directly affect SARS‐CoV‐2, viral respiratory infections often result in bacterial pneumonia. It is possible that some patients die from bacterial co‐infection rather than virus itself. To date, a considerable number of bacterial strains have been resistant to various antibiotics such as azithromycin, and the overuse could render those or other antibiotics even less effective. Therefore, bacterial co‐infection and secondary bacterial infection are considered critical risk factors for the severity and mortality rates of COVID‐19. Also, the antibiotic‐resistant as a result of overusing must be considered. In this review, we will summarize the bacterial co‐infection and secondary bacterial infection in some featured respiratory viral infections, especially COVID‐19.

Oral Microbiome and SARS-CoV-2: Beware of Lung Co-infection

The new coronavirus SARS-CoV-2, the cause of COVID-19, has become a public health emergency of global concern. Like the SARS and influenza pandemics, there have been a large number of cases coinfected with other viruses, fungi, and bacteria, some of which originate from the oral cavity. Capnocytophaga, Veillonella, and other oral opportunistic pathogens were found in the BALF of the COVID-19 patients by mNGS. Risk factors such as poor oral hygiene, cough, increased inhalation under normal or abnormal conditions, and mechanical ventilation provide a pathway for oral microorganisms to enter the lower respiratory tract and thus cause respiratory disease. Lung hypoxia, typical symptoms of COVID-19, would favor the growth of anaerobes and facultative anaerobes originating from the oral microbiota. SARS-CoV-2 may aggravate lung disease by interacting with the lung or oral microbiota via mechanisms involving changes in cytokines, T cell responses, and the effects of host conditions such as aging and the oral microbiome changes due to systemic diseases. Because the oral microbiome is closely associated with SARS-CoV-2 co-infections in the lungs, effective oral health care measures are necessary to reduce these infections, especially in severe COVID-19 patients. We hope this review will draw attention from both the scientific and clinical communities on the role of the oral microbiome in the current global pandemic.

Topological data analysis to model the shape of immune responses during co-infections

Co-infections by multiple pathogens have important implications in many aspects of health, epidemiology and evolution. However, how to disentangle the non-linear dynamics of the immune response when two infections take place at the same time is largely unexplored. Using data sets of the immune response during influenza-pneumococcal co-infection in mice, we employ here topological data analysis to simplify and visualise high dimensional data sets. We identified persistent shapes of the simplicial complexes of the data in the three infection scenarios: single viral infection, single bacterial infection, and co-infection. The immune response was found to be distinct for each of the infection scenarios and we uncovered that the immune response during the co-infection has three phases and two transition points. During the first phase, its dynamics is inherited from its response to the primary (viral) infection. The immune response has an early shift (few hours post co-infection) and then modulates its response to react against the secondary (bacterial) infection. Between 18 and 26 h post co-infection the nature of the immune response changes again and does no longer resembles either of the single infection scenarios.

Co-infection of H9N2 influenza virus and Pseudomonas aeruginosa contributes to the development of hemorrhagic pneumonia in mink

Influenza A virus (IAV) and bacteria co-infection can influence the host clinical conditions. Both H9N2 IAV and Pseudomonas aeruginosa (P. aeruginosa) are potential pathogens of respiratory diseases in mink. In this study, to clarify the effects of H9N2 IAV and P. aeruginosa co-infections on hemorrhagic pneumonia in mink, we carried out to establish the mink models of the two-pathogen co-infections in different orders. Compared with the single infections with H9N2 IAV or P. aeruginosa, the mink co-infected with H9N2 IAV and P. aeruginosa showed severe respiratory diseases, and exacerbated histopathological lesions and more obvious apoptosis in the lung tissues. H9N2 IAV shedding and viral loads in the lungs of the mink co-infected with H9N2 IAV and P. aeruginosa were higher than those in the mink with single H9N2 IAV infection. Furthermore, the clearance of P. aeruginosa in the co-infected mink lungs was delayed. In addition, the anti-H9N2 antibody titers in mink with P. aeruginosa co-infection following H9N2 IAV infection were significantly higher than those of the other groups. This implied that H9N2 IAV and P. aeruginosa co-infection contributed to the development of hemorrhagic pneumonia in mink, and that P. aeruginosa should play a major role in the disease. The exact interaction mechanism among H9N2 IAV, P. aeruginosa and the host needs to be further investigated.

Expression of microRNA in human retinal pigment epithelial cells following infection with Zaire ebolavirus

OBJECTIVE

Survivors of Ebola virus disease (EVD) are at risk of developing blinding intraocular inflammation-or uveitis-which is associated with retinal pigment epithelial (RPE) scarring and persistence of live Zaire ebolavirus (EBOV) within the eye. As part of a large research project aimed at defining the human RPE cell response to being infected with EBOV, this work focused on the microRNAs (miRNAs) associated with the infection.

RESULTS

Using RNA-sequencing, we detected 13 highly induced and 2 highly repressed human miRNAs in human ARPE-19 RPE cells infected with EBOV, including hsa-miR-1307-5p, hsa-miR-29b-3p and hsa-miR-33a-5p (up-regulated), and hsa-miR-3074-3p and hsa-miR-27b-5p (down-regulated). EBOV-miR-1-5p was also found in infected RPE cells. Through computational identification of putative miRNA targets, we predicted a broad range of regulatory activities, including effects on innate and adaptive immune responses, cellular metabolism, cell cycle progression, apoptosis and autophagy. The most highly-connected molecule in the miR-target network was leucine-rich repeat kinase 2, which is involved in neuroinflammation and lysosomal processing. Our findings should stimulate new studies on the impact of miRNA changes in EBOV-infected RPE cells to further understanding of intraocular viral persistence and the pathogenesis of uveitis in EVD survivors.

The Pathobiome in Animal and Plant Diseases

A growing awareness of the diversity and ubiquity of microbes (eukaryotes, prokaryotes, and viruses) associated with larger 'host' organisms has led to the realisation that many diseases thought to be caused by one primary agent are the result of interactions between multiple taxa and the host. Even where a primary agent can be identified, its effect is often moderated by other symbionts. Therefore, the one pathogen-one disease paradigm is shifting towards the pathobiome concept, integrating the interaction of multiple symbionts, host, and environment in a new understanding of disease aetiology. Taxonomically, pathobiomes are variable across host species, ecology, tissue type, and time. Therefore, a more functionally driven understanding of pathobiotic systems is necessary, based on gene expression, metabolic interactions, and ecological processes.

The dynamics between limited-term and lifelong coinfecting bacterial parasites in wild rodent hosts

Interactions between coinfecting parasites may take various forms, either direct or indirect, facilitative or competitive, and may be mediated by either bottom-up or top-down mechanisms. Although each form of interaction leads to different evolutionary and ecological outcomes, it is challenging to tease them apart throughout the infection period. To establish the first step towards a mechanistic understanding of the interactions between coinfecting limited-term bacterial parasites and lifelong bacterial parasites, we studied the coinfection of Bartonella sp. (limited-term) and Mycoplasma sp. (lifelong), which commonly co-occur in wild rodents. We infected Bartonella- and Mycoplasma-free rodents with each species, and simultaneously with both, and quantified the infection dynamics and host responses. Bartonella benefited from the interaction; its infection load decreased more slowly in coinfected rodents than in rodents infected with Bartonella alone. There were no indications for bottom-up effects, but coinfected rodents experienced various changes, depending on the infection stage, in their body mass, stress levels and activity pattern, which may further affect bacterial replication and transmission. Interestingly, the infection dynamics and changes in the average coinfected rodent traits were more similar to the chronic effects of Mycoplasma infection, whereas coinfection uniquely impaired the host's physiological and behavioral stability. These results suggest that parasites with distinct life history strategies may interact, and their interaction may be asymmetric, non-additive, multifaceted and dynamic through time. Because multiple, sometimes contrasting, forms of interactions are simultaneously at play and their relative importance alternates throughout the course of infection, the overall outcome may change under different ecological conditions.

Comorbidity of intestinal helminthiases among malaria outpatients of Wondo Genet health centers, southern Ethiopia: implications for integrated control

Background

It is estimated that over a third of the world population is infected by malaria and helminthiases mainly among communities with high poverty indices. The distribution of these parasitic infections overlaps in many epidemiological settings and have varying outcomes in the host. In this paper we report the prevalence of malaria and intestinal helminthiases coinfections among malaria suspected patients and the association of helminthiases with the occurrence of malaria and its outcomes in Wondo Genet, southern Ethiopia.

Methods

In a cross-sectional study conducted from December 2009 to July 2010 in Kella, Aruma and Busa Health Centers in Wondo Genet, a total of 427 consenting febrile patients were screened for malaria and intestinal helminths infections. Malaria parasite detection and quantification were done using Giemsa stained thick and thin blood films. Helminth infections were screened and quantified by Kato-Katz thick smear method. Haemoglobin level was assessed using haemocue machine (HemoCue HB 201⁺). Difference in proportions and means were tested by Student’s t test and ANOVA while logistic regression analysis was used to determine the association between variables.

Results

Of the total examined, 196 (45.90%) were positive for at least one helminth infection while 276 (64.64%) were positive for malaria. The prevalence of Plasmodium falciparum and P. vivax infections were 47.31 and 16.62%, respectively. The most common helminth parasites detected were Ascaris lumbricoides (33.96%), Trichuris trichiura (21.55%), Schistosoma mansoni (13.35%), and hookworms (6.79%). The overall malaria-helminthiases coinfection was 33.96%. The prevalence of anaemia was 43.12%. Helminthiases coinfection showed a positive correlation with the occurrence of malaria (AOR = 2.17, 95% CI: 1.44–3.28; P < 0.001). Schistosoma mansoni coinfection was associated with the increased risk of developing malaria associated anaemia (OR = 14.4, 95% CI: 1.37–150.80; P = 0.026).

Conclusion

Malaria and helminth coinfections are important causes of morbidities among the population in Wondo Genet necessitating integrated control measures. Nevertheless, further detailed studies on the consequences and pathogenesis of these coinfections are needed to institute sound control and intervention measures.

Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update

Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host-pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas.