Basic concepts in clinical immunology: A review

Immunity is the state of protection against foreign pathogens or substances(antigens). Host defence mechanisms consist of innate immunity (natural immunity), which mediates the initial protection against infections, and adaptive immunity (specific/acquired immunity), which develops more slowly and provides more specialized and more effective defence against infections. The immune system evolved to protect multicellular organisms against pathogens. The body is protected against pathogens by a variety of effector cells and molecules that together make up the immune system. All the cellular elements of blood, including the red blood cells, platelets and white blood cells of the immune system, ultimately derive from the hematopoietic stem cells of the bone marrow. The cells of the adaptive immune system consist of lymphocytes, antigen-presenting cells and effector cells that eliminate microbes. Strategies of avoidance, and tolerance represent different ways of dealing with pathogens. Anatomic barriers and chemical barriers e.g complement and antimicrobial proteins may be considered as primary forms of avoidance.Macrophages,neutrophils and dendritic cells are important cells that that detect infection. Pattern recognition receptors (PRRs) recognize simple molecules and regular patterns of molecular structures called pathogen associated molecular patterns. Some PRR are transmembrane proteins e.g Toll like receptors (TLRs). Vaccination is a simple, safe, and effective way of protecting people against harmful diseases, before they come into contact with them. Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Inappropriate immune responses can result into hypersensitivity, autoimmune disease or immune deficiency.

Interactions Between Glossina Pallidipes Salivary Gland Hypertrophy Virus and Tsetse Endosymbionts in Wild Tsetse Populations

BackgroundTherefore, tsetse control is considered an effective and sustainable tactic for the control of cyclically transmitted trypanosomosis in the absence of effective vaccines and inexpensive, effective drugs. The sterile insect technique (SIT) is currently used to eliminate tsetse fly populations in an area-wide integrated pest management (AW-IPM) context in Senegal. For SIT, tsetse mass-rearing is a major milestone that associated microbes can influence. Tsetse flies can be infected with micro-organisms, including the primary and obligate Wigglesworthia glossinidia, the commensal Sodalis glossinidius, and Wolbachia pipientis. In addition, tsetse populations often carry a pathogenic DNA virus, the Glossina pallidipes Salivary Gland Hypertrophy Virus (GpSGHV) that hinders tsetse fertility and fecundity. Interactions between symbionts and pathogens might affect the performance of the insect host. MethodsIn the present study, we assessed the possible interaction of GpSGHV and tsetse endosymbionts under field conditions to decipher the bidirectional interactions in different Glossina species. We determined the co-infection pattern of GpSGHV and Wolbachia in natural tsetse populations. We further analyzed the interaction of both Wolbachia and GpSGHV infection with Sodalis and Wigglesworthia density using qPCR. ResultsThe results indicated that the co-infection of GpSGHV and Wolbachia was most prevalent in Glossina austeni and Glossina morsitans morsitans, with an explicit significant negative correlation between GpSGHV and Wigglesworthia infection. GpSGHV infection levels of more than 104 were not observed when Wolbachia infection was present at high density (>108.5), suggesting a potential protective role of Wolbachia against GpSGHV. ConclusionThe result indicates that Wolbachia infection might protect tsetse fly against GpSGHV and the interactions between the tsetse host and its associated microbes are dynamic, likely species-specific and significant differences may exist between laboratory and field conditions.

No Evidence of the Vertical Transmission of Non-Virulent Infectious Salmon Anaemia Virus (ISAV-HPR0) in Farmed Atlantic Salmon

The nonvirulent infectious salmon anaemia virus (ISAV-HPR0) is the putative progenitor for virulent-ISAV, and a potential risk factor for the development of infectious salmon anaemia (ISA). Understanding the transmission dynamics of ISAV-HPR0 is fundamental to proper management and mitigation strategies. Here, we demonstrate that ISAV-HPR0 causes prevalent and transient infections in all three production stages of Atlantic salmon in the Faroe Islands. Phylogenetic analysis of the haemagglutinin-esterase gene from 247 salmon showed a clear geographical structuring into two significantly distinct HPR0-subgroups, which were designated G2 and G4. Whereas G2 and G4 co-circulated in marine farms, Faroese broodfish were predominantly infected by G2, and smolt were predominantly infected by G4. This infection pattern was confirmed by our G2- and G4-specific RT-qPCR assays. Moreover, the HPR0 variants detected in Icelandic and Norwegian broodfish were never detected in the Faroe Islands, despite the extensive import of ova from both countries. Accordingly, the vertical transmission of HPR0 from broodfish to progeny is uncommon. Phylogenetic and statistical analysis suggest that HPR0 persists in the smolt farms as “house-strains”, and that new HPR0 variants are occasionally introduced from the marine environment, probably by HPR0-contaminated sea-spray. Thus, high biosecurity—including water and air intake—is required to avoid the introduction of pathogens to the smolt farms.

A Data Analytics Approach for Revealing Influencing Factors of HPV-Related Cancers From Population-Level Statistics Data

Human papillomavirus (HPV) is considered as one of the major causes of multiple cancers, including cervical, anal, and vaginal cancers. Some studies analyzed the infection patterns of cancers caused by HPV using individual clinical test data, which is resource and time expensive. In order to facilitate the understanding of cancers caused by HPV, we propose to use data analytics methods to reveal the influencing factors from the population-level statistics data, which is available more easily. Particularly, we demonstrate the effectiveness of data analytics approach by introducing a predictive analytics method in studying the risk factors of cervix cancer in the United States. Besides accurate prediction of the number of infections, the predictive analytics method discovers the population statistic factors that most affect the cervical cancer infection pattern. Furthermore, we discuss the potential directions in developing more advanced data analytics approaches in studying cancers caused by HPV.

Soil-transmitted helminths, intestinal protozoa and Clonorchis sinensis infections in southeast China

Background Extensive parasitic diseases epidemiology in Zhejiang province has not been carried out since the second national survey in 2004. Therefore, dynamics in prevalence and infection pattern of the major intestinal parasites should be explored. Methods The distribution of three parasites including soil-transmitted helminths (STH), intestinal protozoa and C. sinensis in Zhejiang from 2014 to 2015 were explored. Kato-Katz technique was used for STH and C. sinensis detection, whereas transparent adhesive paper anal swab was used for pinworm detection, and iodine smear was used for protozoa detection. A questionnaire survey on alimentary habits and sanitary behaviors was conducted in half of the studied counties. Results This study recruited 23,552 participants: 19,935 from rural and 3617 from urban area. Overall prevalence of intestinal helminth infections was 1.80%. In this study, seven helminth species were identified including A. duodenale, N. americanus, Trichuris trichiura, Ascaris lumbricoides, C. sinensis, Fasciolopsis buski and pinworm. The average prevalence of STH infection was 1.71%: 1.94% in rural and 0.44% in urban area. Hookworm was the most prevalent infection at 1.58%: 1.79% in rural and 0.44% in urban area. Prevalence varied considerably in the studied counties. Prevalence was highest in Yongkang county at 10.25%. Only 2.79% of children from rural area were infected with pinworm. A proportion of 0.40% of rural participants were infected with protozoa, whereas Endolimax nana was the most prevalent at 0.23%. C. sinensis showed infection only in one man. Awareness on C. sinensis was 24.47% in rural and 45.96% in urban area, respectively. Conclusions Prevalence of STH and protozoa infections declined considerably whereas C. sinensis infections remained few in Zhejiang province compared with the prevalence reported in previous large scale surveys (19.56% for national STH infection in 2004, 18.66% and 4.57% for provincial STH and protozoa infection, respectively in 1999). The findings of this study showed that hookworm, mainly N. americanus remained a parasitic threat to population health, mainly in the central and western Zhejiang. Therefore, more health education regarding fertilization and farming habits is necessary in rural areas. The awareness concerning hookworm infection should be reinforced.

Time-analysis of COVID-19 dispersion among health care workers and the general population

Introduction: Heath care workers with direct (HCW-D) or indirect (HCW-A) patient contact represent 4.2% to 17.8% of COVID-19 cases. We evaluate the temporal COVID-19 infection behavior among HCW-D, HCW-A, and non-HCW. Methods: From February 2020 to April 2021, trained nurses recorded age, gender, occupation, and symptoms in a COVID-19 testing outpatient health center. We allocated data into weekly time fractals and calculated the proportion of COVID-19 positive among HCW vs. non-HCW and incorporated an ARFIMA model (traditionally used in weather forecast) to predict future cases of COVID-19. Results: Among 8,998 COVID-19 RT-PCR tests, 3,462 (42%) patients were HCW-D, and 933 (11%) were HCW-A. Overall, 1,914 (21.3%) returned positive, representing 27%, 25% and 19% of HCW-D, HCW-A and non-HCW, respectively. HCW-D or HCW-A were significantly more likely to test positive for COVID-19 than non-HCW (OR=1.5, p<0.0001). The percentage of positive to negative test results remained steady over time. In the positive cases, the percentage of HCW to non-HCW declined significantly over time (Mann-Kendal trend test: tau=-0.58, p<0.0001). Our ARFIMA model showed a long-memory infection pattern in the occurrence of new COVID-19 cases lasting for months. Average error was 1.9 cases per week comparing predicted to actual values three months later (May-July 2021). Conclusion: HCW have a sustained 50% higher risk of COVID-19 positivity in the pandemic. Time-series analysis showed a long-memory infection pattern with virus spread mainly among HCWs before the general population. The tool http://wdchealth.covid-map.com/shiny/covid-map/ will be updated according to population previous infection and vaccination impact.

The role of Epstein–Barr virus-encoded latent membrane proteins in host immune escape

Epstein–Barr virus (EBV) is a type IV herpesvirus that widely infects the vast majority of adults, and establishes a latent infection pattern in host cells to escape the clearance of immune system. The virus is intimately associated with the occurrence and progression of lymphomas and epithelial cell cancers. EBV latent membrane proteins (LMPs) can assist its immune escape by downregulating host immune response. Besides EBV, LMPs have important effects on the functions of exosomes and autophagy, which also help EBV to escape immune surveillance. These escape mechanisms may provide conditions for further development of EBV-associated tumors. In this article, we discussed the potential functions of EBV-encoded LMPs in promoting immune escape.

Comprehensive Description of Pathogens and Antibiotic Treatment Guidance in Children With Community-Acquired Pneumonia Using Combined Mass Spectrometry Methods

The objective of this study was to evaluate the value of molecular methods in the management of community-acquired pneumonia (CAP) in children. Previously developed mass spectrometry (MS)-based methods combined with quantitative real-time PCR (combined-MS methods) were used to describe the aetiology and evaluate antibiotic therapy in the enrolled children. Sputum collected from 302 children hospitalized with CAP were analyzed using the combined-MS methods, which can detect 19 viruses and 12 bacteria related to CAP. Based on the results, appropriate antibiotics were determined using national guidelines and compared with the initial empirical therapies. Respiratory pathogens were identified in 84.4% of the patients (255/302). Co-infection was the predominant infection pattern (51.7%, 156/302) and was primarily a bacterial-viral mixed infection (36.8%, 111/302). Compared with that using culture-based methods, the identification rate for bacteria using the combined-MS methods (61.8%, 126/204) increased by 28.5% (p &lt;0.001). Based on the results of the combined-MS methods, the initial antibiotic treatment of 235 patients was not optimal, which mostly required switching to β-lactam/β-lactamase inhibitor combinations or reducing unnecessary macrolide treatments. Moreover, using the combined-MS methods to guide antibiotic therapy showed potential to decrease the length of stay in children with severe CAP. For children with CAP, quantitative molecular testing on sputum can serve as an important complement to traditional culture methods. Early aetiology elucidated using molecular testing can help guide the antibiotic therapy.

Prevalence of Intestinal Parasites among Patients Attending Zella Central Laboratory, Zella City, Libya

Intestinal parasites have become one of the most important health problems for public health experts and decision-makers in many countries. In Zella city, the prevalence of intestinal parasites was not studied before, therefore, the current study was conducted to identify the intestinal parasites in Zella city. The data in this study was collected from the records of the central laboratory in Zella city over the period of time, from the beginning of 2015, till the end of 2019. A 839 samples were examined, and 728 samples were infected with parasites, which represent 87%. The results of the study revealed the presence of four types of intestinal parasites with different proportions as follows: Entamoeba histolytica by 65%, Ascaris lumbricoides by 24%, and Entamoeba coli by 10%, and Giardia lamblia by 0.7%. The results of the study also indicate that the infection rate of males and females were very close, 86% and 87%, respectively. The results of the current study also indicate that the single type infection pattern was the most common compared to the mixed parasite infection, 95%, and 5%, respectively. The study also shows that the percentage of intestinal parasites infection was higher during the autumn and spring seasons. Despite the increase in cultural and social awareness and the improvement of the living conditions of many families, the rate of intestinal parasites infection is still high, which requires more investigations.

Determinants of haemosporidian single and co-infections risks in western paleartic birds

Co-infections with multiple pathogens are common in the wild and may act as a strong selective pressure on both host and parasite evolution. Yet, contrary to single infection, the factors that shape co-infection risk are largely under-investigated. Here, we explored the extent to which bird ecology and phylogeny impact single and co-infection probabilities by haemosporidian parasites using large datasets from museum collections and a Bayesian phylogenetic modelling framework. While both phylogeny and species attributes (e.g. size of the geographic range, life-history strategy, migration) were relevant predictors of co-infection risk, these factors were less pertinent in predicting the probability of being single infected. Our study suggests that co-infection risk is under a stronger deterministic control than single-infection risk. These results underscore the combined influence of host evolutionary history and species attributes in determining single and co-infection pattern providing new avenues regarding our ability to predict infection risk in the wild.