Telomere Length in a South African Population Co-Infected with HIV and Helminths

Biological ageing refers to the gradual decrease in physiological functions, resulting in immune senescence, cellular damage and apoptosis. Telomere length is a biomarker of biological ageing. Limited studies have associated shorter telomere length with HIV and parasite single infections, with no studies reporting the association of HIV and parasite co-infection with telomere length. The study aimed to investigate whether telomere length shortening is accelerated in a South African population co-infected with HIV and helminths compared to participants singly infected with either HIV or helminths. Additionally, telomere length data were compared with participants' biochemical and full blood count parameters. A total of 200 participants were in groups of uninfected control, HIV single infection, helminth single infection and HIV and helminth co-infection groups. Relative telomere length (RTL) was determined using Real-Time PCR and associated with biochemical and full blood count parameters using multivariate regression analysis models that were adjusted for confounders. The uninfected control group was used as a reference group. The uninfected control group had the highest mean RTL (1.21 ± 0.53) while the HIV-infected (0.96 ± 0.42) and co-infected (0.93 ± 0.41) groups had similar RTLs, and lastly, the helminth-infected group (0.83 ± 0.33) had the lowest RTL (p = 0.0002). When compared to the uninfected control group, a significant association between RTL and biochemical parameters, including blood iron (β = -0.48), ferritin (β = -0.48), transferrin saturation (β = -0.57), transferrin (β = -0.57), phosphate (β = -0.47), vitamin A (β = -0.49) and C-reactive protein (β = -0.52) were noted in the co-infected group (p < 0.05). In addition, a significant association between RTL and full blood count, including (β = -0.47), haematocrit (β = -0.46), mean corpuscular volume (β = -0.47), lymphocytes (β = -0.45), mean corpuscular haemoglobin concentration (β = -0.45), red cell distribution width (β = -0.47), monocytes (β = -0.45), eosinophils (β = -0.45), basophils (β = -0.44) and transferrin saturation (β = -0.57) were also noted in the co-infected group (p < 0.05). Accelerated biological ageing, as indicated by telomere length shortening, is associated with HIV and helminth co-infections.

Impact factors of Blastocystis hominis infection in persons living with human immunodeficiency virus: a large-scale, multi-center observational study from China

BACKGROUND

Blastocystis hominis (Bh) is zoonotic parasitic pathogen with a high prevalent globally, causing opportunistic infections and diarrhea disease. Human immunodeficiency virus (HIV) infection disrupts the immune system by depleting CD4+ T lymphocyte (CD4+ T) cell counts, thereby increasing Bh infection risk among persons living with HIV (PLWH). However, the precise association between Bh infection risk and HIV-related biological markers and treatment processes remains poorly understood. Hence, the purpose of the study was to explore the association between Bh infection risk and CD4+ T cell counts, HIV viral load (VL), and duration of interruption in antiviral therapy among PLWH.

METHODS

A large-scale multi-center cross-sectional study was conducted in China from June 2020 to December 2022. The genetic presence of Bh in fecal samples was detected by real-time fluorescence quantitative polymerase chain reaction, the CD4+ T cell counts in venous blood was measured using flowcytometry, and the HIV VL in serum was quantified using fluorescence-based instruments. Restricted cubic spline (RCS) was applied to assess the non-linear association between Bh infection risk and CD4+ T cell counts, HIV VL, and duration of interruption in highly active antiretroviral therapy (HARRT).

RESULTS

A total of 1245 PLWH were enrolled in the study, the average age of PLWH was 43 years [interquartile range (IQR): 33, 52], with 452 (36.3%) being female, 50.4% (n = 628) had no immunosuppression (CD4+ T cell counts > 500 cells/μl), and 78.1% (n = 972) achieved full virological suppression (HIV VL < 50 copies/ml). Approximately 10.5% (n = 131) of PLWH had interruption. The prevalence of Bh was found to be 4.9% [95% confidence interval (CI): 3.8-6.4%] among PLWH. Significant nonlinear associations were observed between the Bh infection risk and CD4+ T cell counts (Pfor nonlinearity < 0.001, L-shaped), HIV VL (Pfor nonlinearity < 0.001, inverted U-shaped), and duration of interruption in HARRT (Pfor nonlinearity < 0.001, inverted U-shaped).

CONCLUSIONS

The study revealed that VL was a better predictor of Bh infection than CD4+ T cell counts. It is crucial to consider the simultaneous surveillance of HIV VL and CD4+ T cell counts in PLWH in the regions with high level of socioeconomic development. The integrated approach can offer more comprehensive and accurate understanding in the aspects of Bh infection and other opportunistic infections, the efficacy of therapeutic drugs, and the assessment of preventive and control strategies.

Booster Vaccination Against SARS-CoV-2 Induces Potent Immune Responses in People With Human Immunodeficiency Virus

BACKGROUND

People with human immunodeficiency virus (HIV) on antiretroviral therapy (ART) with good CD4 T-cell counts make effective immune responses following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are few data on longer term responses and the impact of a booster dose.

METHODS

Adults with HIV were enrolled into a single arm open label study. Two doses of ChAdOx1 nCoV-19 were followed 12 months later by a third heterologous vaccine dose. Participants had undetectable viraemia on ART and CD4 counts >350 cells/µL. Immune responses to the ancestral strain and variants of concern were measured by anti-spike immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), MesoScale Discovery (MSD) anti-spike platform, ACE-2 inhibition, activation induced marker (AIM) assay, and T-cell proliferation.

FINDINGS

In total, 54 participants received 2 doses of ChAdOx1 nCoV-19. 43 received a third dose (42 with BNT162b2; 1 with mRNA-1273) 1 year after the first dose. After the third dose, total anti-SARS-CoV-2 spike IgG titers (MSD), ACE-2 inhibition, and IgG ELISA results were significantly higher compared to Day 182 titers (P < .0001 for all 3). SARS-CoV-2 specific CD4+ T-cell responses measured by AIM against SARS-CoV-2 S1 and S2 peptide pools were significantly increased after a third vaccine compared to 6 months after a first dose, with significant increases in proliferative CD4+ and CD8+ T-cell responses to SARS-CoV-2 S1 and S2 after boosting. Responses to Alpha, Beta, Gamma, and Delta variants were boosted, although to a lesser extent for Omicron.

CONCLUSIONS

In PWH receiving a third vaccine dose, there were significant increases in B- and T-cell immunity, including to known variants of concern (VOCs).

Lateral Flow Immunoassays for Detecting Viral Infectious Antigens and Antibodies

Abundant immunological assays currently exist for detecting pathogens and identifying infected individuals, making detection of diseases at early stages integral to preventing their spread, together with the consequent emergence of global health crises. Lateral flow immunoassay (LFIA) is a test characterized by simplicity, low cost, and quick results. Furthermore, LFIA testing does not need well-trained individuals or laboratory settings. Therefore, it has been serving as an attractive tool that has been extensively used during the ongoing COVID-19 pandemic. Here, the LFIA strip's available formats, reporter systems, components, and preparation are discussed. Moreover, this review provides an overview of the current LFIAs in detecting infectious viral antigens and humoral responses to viral infections.

Lateral flow assays for viruses diagnosis: Up-to-date technology and future prospects

Bacteria, viruses, and parasites are harmful microorganisms that cause infectious diseases. Early detection of diseases is critical to prevent disease transmission and provide epidemic preparedness, as these can cause widespread deaths and public health crises, particularly in resource-limited countries. Lateral flow assay (LFA) systems are simple-to-use, disposable, inexpensive diagnostic devices to test biomarkers in blood and urine samples. Thus, LFA has recently received significant attention, especially during the pandemic. Here, first of all, the design principles and working mechanisms of existing LFA methods are examined. Then, current LFA implementation strategies are presented for communicable disease diagnoses, including COVID-19, zika and dengue, HIV, hepatitis, influenza, malaria, and other pathogens. Furthermore, this review focuses on an overview of current problems and accessible solutions in detecting infectious agents and diseases by LFA, focusing on increasing sensitivity with various detection methods. In addition, future trends in LFA-based diagnostics are envisioned.

The burden of influenza among Kenyan pregnant and postpartum women and their infants, 2015–2020

Background

In tropical Africa, data about influenza‐associated illness burden are needed to assess potential benefits of influenza vaccination among pregnant women. We estimated the incidence of influenza among pregnant women and their infants in Siaya County, Kenya.

Methods

We enrolled women at <31 weeks of gestation and conducted weekly follow‐up until 6‐month postpartum to identify acute respiratory illnesses (ARIs). We defined ARI among mothers as reported cough, rhinorrhoea or sore throat and among infants as maternal‐reported cough, difficulty breathing, rhinorrhoea or clinician diagnosis of respiratory illness. We collected nasal/nasopharyngeal and oropharyngeal swabs from mothers/infants with ARI and tested for influenza A and B using molecular assays. We calculated antenatal incidence of laboratory‐confirmed influenza among mothers and postnatal incidence among mothers and infants.

Results

During June 2015 to May 2020, we analysed data from 3,026 pregnant women at a median gestational age of 16 weeks (interquartile range [IQR], 13, 18) and followed 2,550 infants. Incidence of laboratory‐confirmed influenza during pregnancy (10.3 episodes per 1,000 person‐months [95% confidence interval {CI} 8.6–11.8]) was twofold higher than in the postpartum period (4.0 [95% CI 2.6–5.5]; p < 0.01). Incidence was significantly higher among human immunodeficiency virus (HIV)‐infected pregnant women (15.6 [95% CI 11.0–20.6] vs. 9.1 [95% CI 7.5–10.8]; p < 0.01). Incidence among young infants was 4.4 (95% CI 3.0–5.9) and similar among HIV‐exposed and HIV‐unexposed infants.

Conclusion

Our findings suggest a substantial burden of influenza illnesses during pregnancy, with a higher burden among HIV‐infected mothers. Kenyan authorities should consider the value of vaccinating pregnant women, especially if HIV infected.

Intestinal Parasitosis and its Association with CD4+ T Cell Count and Viral Load among People Living with HIV in Parasite Endemic Settings of Northwest Ethiopia

Purpose

To study intestinal parasitosis and its association with viral load and CD4+ T cell count in HIV-infected individuals at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia.

Methods

A cross-sectional study was conducted from March to June 2019. Three hundred and sixteen study participants were selected using systematic random sampling technique. Sociodemographic and clinical data were collected using structured questionnaire. Stool samples were collected and examined using direct saline, formol ether concentration technique and modified acid fast staining. CD4+ T cell counts and viral load were determined by fluorescence-activated cell sorting (BD FACS) and COBAS Ampliprep/COBAS TaqMan HI2CAP assay, respectively. Data were entered into Epi Data 3.1 and transferred to SPSS version 20 software for analysis. Bivariable and multivariable analyses were performed using a binary logistic regression model. P values of less than 0.05 were considered statistically significant.

Results

The overall prevalence of intestinal parasitosis was 24.7% (78/316). The most commonly detected parasite was Cryptosporidium species with 5.4% (17/316), followed by Ascaris lumbricoides with 5.1% (16/316). There was a significant association with low CD4+ T cell count (AOR: 3.207; 95% CI: 1.237, 8.317), high viral load (AOR: 2.933; 95% CI: 1.326, 6.489), individuals aged 31–40 years (AOR: 0.305; 95% CI: 0.124, 0.751) and individuals aged 41–50 years (AOR: 0.261; 95% CI: 0.101, 0.671).

Conclusion

In this study, prevalence of intestinal parasitic infections was high and was associated with low CD4+ T cell count and high viral load. Therefore, screening of HIV patients, especially those with low CD4+ T-cell count and high viral load, particularly for opportunistic intestinal parasitic infections would be of utmost importance in the efforts to prevent and control opportunistic infections in HIV patients.

Helminth infections and immunosenescence: The friend of my enemy

Age-associated alterations of the immune system, which known as "immunosenescence", is characterized by a decline in innate and adaptive immunity, which leading to increased susceptibility to age-associated diseases, such as infectious diseases, rheumatic disease and malignancies. On the other hand, helminth infections are among the most prevalent infections in older individuals, especially in the nursing homes. Most of helminth infections have minor clinical symptoms and usually causing chronic infections without treatment. Nevertheless, chronic helminthiasis alters immune responses somewhat similar to the immunosenescence. Some similarities also exist between helminth infections and immunosenescence: 1) both of them led to declining the immune responses; 2) undernutrition is a consequence of immunosenescence and helminthiasis; 3) vaccine efficacy declines in aging and individuals with helminth infections; 4) increase incidence and prevalence of infectious diseases in the elder individuals and patients with helminth infections; and 5) both of them promote tumorigenesis. Hence, it is probable that helminth infections in the elderly population can intensify the immunosenescence outcomes due to the synergistic immunoregulatory effects of each of them. It would be suggested that, diagnosis, treatment and prevention of helminth infections should be more considered in older individuals. Also, it would be suggested that helminths or their antigens can be used for investigation of immunosenescence because both of them possess some similarities in immune alterations. Taken together, this review offers new insights into the immunology of aging and helminth infections.

Zika Virus Infection and Differential Diagnosis in a Cohort of HIV-Infected Patients

BACKGROUND

Zika virus (ZIKV) emergence in South America revealed the lack of knowledge regarding clinical manifestations in HIV-infected individuals.

OBJECTIVES

We described the clinical characteristics, laboratory manifestations, differential diagnosis, and outcome of ZIKV infection in a large, single-center cohort of HIV-infected patients.

METHODS

HIV-infected patients aged 18 years and older with clinical suspected arboviral disease from an ongoing cohort were followed from February 2015 through December 2015. Acute serum samples were tested for ZIKV, dengue virus (DENV), and chikungunya virus by real-time reverse transcriptase polymerase chain reaction, anti-DENV immunoglobulin (Ig)M/IgG, and syphilis assays; convalescent samples were tested for anti-DENV IgM/IgG; and urine samples were tested for ZIKV by real-time reverse transcriptase polymerase chain reaction. ZIKV disease was defined according to the Pan American Health Organization (PAHO) guidelines.

RESULTS

Of 101 patients, ZIKV was confirmed in 43 cases and suspected in 34, and another diagnosis was assumed for 24 patients (dengue, secondary/latent syphilis, respiratory infections, human parvovirus B19, adverse drug reaction, musculoskeletal disorders, and acute gastroenteritis). ZIKV-confirmed and ZIKV-suspected patients reported similar signs and symptoms. Pruritic rash was the most common symptom, followed by myalgia, nonpurulent conjunctivitis, arthralgia, prostration, and headache. In the short-term follow-up [median 67.5 days (interquartile range: 32-104.5)], CD4 cell count (Z = -0.831, P = 0.406) and HIV viral load (Z = -0.447, P = 0.655) did not change significantly after ZIKV infection. There were no hospitalizations, complications, or deaths.

CONCLUSIONS

Among HIV-infected patients with suspected arboviral disease, 42.6% were ZIKV-infected. CD4 cell counts and HIV viral load were not different after ZIKV infection. Differential diagnosis with other diseases and adverse drug reaction should be evaluated.

Infection against infection: parasite antagonism against parasites, viruses and bacteria

Background

Infectious diseases encompass a large spectrum of diseases that threaten human health, and coinfection is of particular importance because pathogen species can interact within the host. Currently, the antagonistic relationship between different pathogens during concurrent coinfections is defined as one in which one pathogen either manages to inhibit the invasion, development and reproduction of the other pathogen or biologically modulates the vector density. In this review, we provide an overview of the phenomenon and mechanisms of antagonism of coinfecting pathogens involving parasites.

Main body

This review summarizes the antagonistic interaction between parasites and parasites, parasites and viruses, and parasites and bacteria. At present, relatively clear mechanisms explaining polyparasitism include apparent competition, exploitation competition, interference competition, biological control of intermediate hosts or vectors and suppressive effect on transmission. In particular, immunomodulation, including the suppression of dendritic cell (DC) responses, activation of basophils and mononuclear macrophages and adjuvant effects of the complement system, is described in detail.

Conclusions

In this review, we summarize antagonistic concurrent infections involving parasites and provide a functional framework for in-depth studies of the underlying mechanisms of coinfection with different microorganisms, which will hasten the development of promising antimicrobial alternatives, such as novel antibacterial vaccines or biological methods of controlling infectious diseases, thus relieving the overwhelming burden of ever-increasing antimicrobial resistance.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0560-6) contains supplementary material, which is available to authorized users.

Household socio-economic position and individual infectious disease risk in rural Kenya

The importance of household socio-economic position (SEP) in shaping individual infectious disease risk is increasingly recognised, particularly in low income settings. However, few studies have measured the extent to which this association is consistent for the range of pathogens that are typically endemic among the rural poor in the tropics. This cross-sectional study assessed the relationship between SEP and human infection within a single community in western Kenya using a set of pathogens with diverse transmission routes. The relationships between household SEP and individual infection with Plasmodium falciparum, hookworm (Ancylostoma duodenale and/or Necator americanus), Entamoeba histolytica/dispar, Mycobacterium tuberculosis, and HIV, and co-infections between hookworm, P. falciparum and E. histolytica/dispar, were assessed using multivariable logistic and multinomial regression. Individuals in households with the lowest SEP were at greatest risk of infection with P. falciparum, hookworm and E. histolytica/dispar, as well as co-infection with each pathogen. Infection with M. tuberculosis, by contrast, was most likely in individuals living in households with the highest SEP. There was no evidence of a relationship between individual HIV infection and household SEP. We demonstrate the existence of a household socio-economic gradient within a rural farming community in Kenya which impacts upon individual infectious disease risk. Structural adjustments that seek to reduce poverty, and therefore the socio-economic inequalities that exist in this community, would be expected to substantially reduce overall infectious disease burden. However, policy makers and researchers should be aware that heterogeneous relationships can exist between household SEP and infection risk for different pathogens in low income settings.

Spatial and Temporal Mapping of Human Innate Lymphoid Cells Reveals Elements of Tissue Specificity

Innate lymphoid cells (ILC) play critical roles in regulating immunity, inflammation, and tissue homeostasis in mice. However, limited access to non-diseased human tissues has hindered efforts to profile anatomically-distinct ILCs in humans. Through flow cytometric and transcriptional analyses of lymphoid, mucosal, and metabolic tissues from previously healthy human organ donors, here we have provided a map of human ILC heterogeneity across multiple anatomical sites. In contrast to mice, human ILCs are less strictly compartmentalized and tissue localization selectively impacts ILC distribution in a subset-dependent manner. Tissue-specific distinctions are particularly apparent for ILC1 populations, whose distribution was markedly altered in obesity or aging. Furthermore, the degree of ILC1 population heterogeneity differed substantially in lymphoid versus mucosal sites. Together, these analyses comprise a comprehensive characterization of the spatial and temporal dynamics regulating the anatomical distribution, subset heterogeneity, and functional potential of ILCs in non-diseased human tissues.

Symptoms of infectious diseases in HIV-positive travellers: A prospective study with exposure-matched controls

BACKGROUND

Recently, the number of HIV-infected travellers to (sub)tropical areas has increased substantially. In the Netherlands, HIV-positive travellers with CD4-cells of <500/mm³ are advised to carry stand-by antibiotic treatment against travellers' diarrhoea. Our aim was to determine whether HIV infection is associated with travel-related symptomatic diseases.

METHODS

A prospective study was performed among HIV-infected travellers and age-matched HIV-uninfected travel companions serving as controls, attending two travel clinics in Amsterdam. Participants filled out daily questionnaires before, during, and after their trip.

RESULTS

Overall, 52 pairs were included. All participants were male, and 91.3% were born in a Western country. Prevalence of travel-related diarrhoea was 50% among HIV-positive travellers and 40% among controls. No significant differences were observed for incident travel-related diarrhoea (incidence rate ratio = 1.60, 95%CI = 0.79-3.27) or duration of symptoms (odds ratio = 1.49, 95%CI = 0.65-3.45). There were no significant differences in symptom incidence or duration for travel-related vomiting, cough, rhinitis, pruritus, fatigue, or nausea. Only 6.3% of HIV-positive travellers with CD4-cells of <500/mm³ and diarrhoea used their stand-by antibiotic treatment as recommended.

CONCLUSION

Travel-related symptoms were not significantly more frequent or longer lasting among HIV-infected travellers compared to controls. Most HIV-infected travellers with CD4-cells of <500/mm³ and diarrhoea did not take stand-by antibiotic treatment. These results may question the need for routine prescription of stand-by antibiotics among this specific risk group. Further research, especially among HIV infected VFR travellers and in larger study groups is needed.

Malaria and HIV coinfection in sub-Saharan Africa: prevalence, impact, and treatment strategies

Malaria and HIV, two of the world's most deadly diseases, are widespread, but their distribution overlaps greatly in sub-Saharan Africa. Consequently, malaria and HIV coinfection (MHC) is common in the region. In this paper, pertinent publications on the prevalence, impact, and treatment strategies of MHC obtained by searching major electronic databases (PubMed, PubMed Central, Google Scholar, ScienceDirect, and Scopus) were reviewed, and it was found that the prevalence of MHC in SSA was 0.7%-47.5% overall. Prevalence was 0.7%-47.5% in nonpregnant adults, 1.2%-27.8% in children, and 0.94%-37% in pregnant women. MHC was associated with an increased frequency of clinical parasitemia and severe malaria, increased parasite and viral load, and impaired immunity to malaria in nonpregnant adults, children, and pregnant women, increased in placental malaria and related outcomes in pregnant women, and impaired antimalarial drug efficacy in nonpregnant adults and pregnant women. Although a few cases of adverse events have been reported in coinfected patients receiving antimalarial and antiretroviral drugs concurrently, available data are very limited and have not prompted major revision in treatment guidelines for both diseases. Artemisinin-based combination therapy and cotrimoxazole are currently the recommended drugs for treatment and prevention of malaria in HIV-infected children and adults. However, concurrent administration of cotrimoxazole and sulfadoxine-pyrimethamine in HIV-infected pregnant women is not recommended, because of high risk of sulfonamide toxicity. Further research is needed to enhance our understanding of the impact of malaria on HIV, drug-drug interactions in patients receiving antimalarials and antiretroviral drugs concomitantly, and the development of newer, safer, and more cost-effective drugs and vaccines to prevent malaria in HIV-infected pregnant women.

Current concerns and perspectives on Zika virus co-infection with arboviruses and HIV

Dissemination of vector-borne viruses, such as Zika virus (ZIKV), in tropical and sub-tropical regions has a complicated impact on the immunopathogenesis of other endemic viruses such as dengue virus (DENV), chikungunya virus (CHIKV) and human immunodeficiency virus (HIV). The consequences of the possible co-infections with these viruses have specifically shown significant impact on the treatment and vaccination strategies. ZIKV is a mosquito-borne flavivirus from African and Asian lineages that causes neurological complications in infected humans. Many of DENV and CHIKV endemic regions have been experiencing outbreaks of ZIKV infection. Intriguingly, the mosquitoes, Aedes Aegypti and Aedes Albopictus, can simultaneously transmit all the combinations of ZIKV, DENV, and CHIKV to the humans. The co-circulation of these viruses leads to a complicated immune response due to the pre-existence or co-existence of ZIKV infection with DENV and CHIKV infections. The non-vector transmission of ZIKV, especially, via sexual intercourse and placenta represents an additional burden that may hander the treatment strategies of other sexually transmitted diseases such as HIV. Collectively, ZIKV co-circulation and co-infection with other viruses have inevitable impact on the host immune response, diagnosis techniques, and vaccine development strategies for the control of these co-infections.

[Zika virus infection and the nervous system]

Zika virus is an arbovirus from the family of flaviviruses, which is transmitted by the mosquito Aedes aegyptii and also by the Asian mosquito Aedes albopticus. The largest observed Zika virus epidemic is currently taking place in North and South America, in the Caribbean, southern USA and Southeast Asia. In most cases the infection is an unspecific, acute, febrile disease. Neurological manifestations consist mainly of microcephaly in newborns and Guillain-Barré syndrome but other rare manifestations have also become known in the meantime, such as meningoencephalitis and myelitis. Therefore, the Zika virus, similar to other flaviviruses, has neuropathogenic properties. In particular, the drastic increase in microcephaly cases in Brazil has induced great research activities. The virus is transmitted perinatally and can be detected in the amniotic fluid, placenta and brain tissue of the newborn. Vaccination or a causal therapy does not yet exist. The significant increase in Guillain-Barré syndrome induced by the Zika virus was observed during earlier outbreaks. In the meantime, scientifically clear connections between a Zika virus infection and these neurological manifestations have been shown. Long-term studies and animal models should be used for a better understanding of the pathomechanisms of this disease.

Dengue Virus Coinfection in Human Immunodeficiency Virus-1-Infected Patients on the West Coast of Mexico

Dengue virus infection in human immunodeficiency virus (HIV)-positive patients is not well studied. Previous reports suggest a transitory inhibition of the HIV-1 viral load, as well as a benign clinical progression of dengue. The follow-up of six HIV-1-infected patients, diagnosed and hospitalized with dengue virus infection in the State of Colima, Mexico, was carried out to analyze the progression of this viral coinfection. The presence of dengue virus serotype 1 was confirmed through molecular tests. No severe complications were observed in any of the patients during dengue virus infection. Significant alteration of the HIV-1 viral loads was not observed during dengue virus infection and 6 months after coinfection. Further studies are required to understand the pathology, as well as the clinical course, of these viral coinfections.

The Interaction between HIV and Intestinal Helminth Parasites Coinfection with Nutrition among Adults in KwaZulu-Natal, South Africa

In South Africa few studies have examined the effects of the overlap of HIV and helminth infections on nutritional status. This cross-sectional study investigated the interaction between HIV and intestinal helminths coinfection with nutritional status among KwaZulu-Natal adults. Participants were recruited from a comprehensive primary health care clinic and stratified based on their HIV, stool parasitology, IgE, and IgG4 results into four groups: the uninfected, HIV infected, helminth infected, and HIV-helminth coinfected groups. The nutritional status was assessed using body mass index, 24-hour food recall, micro-, and macronutrient biochemical markers. Univariate and multivariate multinomial probit regression models were used to assess nutritional factors associated with singly and dually infected groups using the uninfected group as a reference category. Biochemically, the HIV-helminth coinfected group was associated with a significantly higher total protein, higher percentage of transferrin saturation, and significantly lower ferritin. There was no significant association between single or dual infections with HIV and helminths with micro- and macronutrient deficiency; however general obesity and low micronutrient intake patterns, which may indicate a general predisposition to micronutrient and protein-energy deficiency, were observed and may need further investigations.

Phylogenetic analysis of genetically distinct Enterocytozoon bieneusi infecting renal transplant recipients

Enterocytozoon bieneusi (E. bieneusi), infecting renal transplant (RT) recipients may be transmitted anthroponotically or zoonotically. Accordingly, we aimed to, a) evaluate genotypes of E. bieneusi ínfecting RT recipients, and b) infer phylogenetic interpretation on transmission of different genotypes among infected hosts. Stool samples of 22 RT recipients infected with microsporidia (identified using modified trichrome staining) were subjected to species identification. All E. bieneusi positive samples were subjected to genotyping. The phylogenetic tree was constructed using Mega 5 software. Of 22 microsporidia infected RT recipients, 21 (95.5%) had E. bieneusi. ITS sequences of 21 E. bieneusi were classified into eight genotypes (Ind1 to Ind8). Among them, 4 (Ind5 to Ind8) were novel. Genotypes Ind2, Ind3, Ind4, Ind7 and Ind8 showed close sequence similarity to genotypes reported exclusively from humans. Phylogenetic analysis further supported their anthroponotic transmission. Genotypes Ind1, Ind5 and Ind6 showed close sequence similarity to genotypes reported from both animals and humans. Phylogenetic analysis further supported their zoonotic transmission. Anthroponotic transmission of E. bieneusi was more common among males (11, 100% vs. 7/10, 70%; P = 0.05), presenting with diarrhea (11, 100% vs. 6/10, 60%; P = 0.02) and watery stool (10/11, 91% vs. 5/10, 50%; P = 0.03).

HIV-1 Tat protein enhances the intracellular growth of Leishmania amazonensis via the ds-RNA induced protein PKR

HIV-1 co-infection with human parasitic diseases is a growing public health problem worldwide. Leishmania parasites infect and replicate inside macrophages, thereby subverting host signaling pathways, including the response mediated by PKR. The HIV-1 Tat protein interacts with PKR and plays a pivotal role in HIV-1 replication. This study shows that Tat increases both the expression and activation of PKR in Leishmania-infected macrophages. Importantly, the positive effect of Tat addition on parasite growth was dependent on PKR signaling, as demonstrated in PKR-deficient macrophages or macrophages treated with the PKR inhibitor. The effect of HIV-1 Tat on parasite growth was prevented when the supernatant of HIV-1-infected macrophages was treated with neutralizing anti-HIV-1 Tat prior to Leishmania infection. The addition of HIV-1 Tat to Leishmania-infected macrophages led to inhibition of iNOS expression, modulation of NF-kB activation and enhancement of IL-10 expression. Accordingly, the expression of a Tat construct containing mutations in the basic region (49–57aa), which is responsible for the interaction with PKR, favored neither parasite growth nor IL-10 expression in infected macrophages. In summary, we show that Tat enhances Leishmania growth through PKR signaling.

First detection of autochthonous Zika virus transmission in a HIV-infected patient in Rio de Janeiro, Brazil

Since May 2015, Brazil's Ministry of Health has reported autochthonous transmission of Zika virus (ZIKV) in some states of the country. Simultaneous circulation of Dengue, Chikungunya and ZIKV in the country hinder both the diagnosis and the therapeutic approach of patients seeking care with acute febrile illnesses especially in patients with comorbidities. The association between HIV infection and endemic diseases has been described especially in tropical regions with varying levels of complications, although there has been no report of ZIKV in HIV-infected patients. We report the first autochthonous case of laboratory confirmed ZIKV infection in a HIV-infected patient in Rio de Janeiro, Brazil. He evolved with only mild symptoms and recovered well without major laboratory abnormalities. Phylogenetic analysis of the ZIKV detected in the patient sera clustered within the Asian clade. To the best of our knowledge, this is the first time that Zika virus co-infection is reported in a HIV-infected patient.

Effect of deworming on disease progression markers in HIV-1-infected pregnant women on antiretroviral therapy: a longitudinal observational study from Rwanda

BACKGROUND

Deworming human immunodeficiency virus (HIV)-infected individuals on antiretroviral therapy (ART) may be beneficial, particularly during pregnancy. We determined the efficacy of targeted and nontargeted antihelminth therapy and its effects on Plasmodium falciparum infection status, hemoglobin levels, CD4 counts, and viral load in pregnant, HIV-positive women receiving ART.

METHODS

Nine hundred eighty HIV-infected pregnant women receiving ART were examined at 2 visits during pregnancy and 2 postpartum visits within 12 weeks. Women were given antimalarials when malaria-positive whereas albendazole was given in a targeted (n = 467; treatment when helminth stool screening was positive) or nontargeted (n = 513; treatment at all time points, with stool screening) fashion.

RESULTS

No significant differences were noted between targeted and nontargeted albendazole treatments for the variables measured at each study visit except for CD4 counts, which were lower (P < .05) in the latter group at the final visit. Albendazole therapy was associated with favorable changes in subjects' hemoglobin levels, CD4 counts, and viral loads, particularly with helminth infections.

CONCLUSIONS

Antihelminthic therapy reduces detectable viral load, and increases CD4 counts and hemoglobin levels in pregnant HIV-infected women with helminth coinfections receiving ART.

Infectious diarrhoea in antiretroviral therapy-naive HIV/AIDS patients in Kenya

BACKGROUND

Diarrhoea is a significant cause of morbidity and mortality in immunocompromised patients. The objectives of this study were to investigate the aetiological agents, risk factors and clinical features associated with diarrhoea in HIV/AIDS patients in Kenya.

METHODS

Sociodemographic, epidemiological and clinical data were obtained for 164 HIV/AIDS patients (70 with and 94 without diarrhoea) recruited from Kenyatta National Hospital, Kenya. Stool samples were examined for enteric pathogens by microscopy and bacteriology.

RESULTS

Intestinal protozoa and fungi were identified in 70% of patients, more frequently in those with diarrhoea (p<0.001). Helminths were detected in 25.6% of patients overall, and bacterial pathogens were identified in 51% of patients with diarrhoea. Polyparasitism was more common in patients with diarrhoea than those without (p<0.0001). Higher CD4(+) T-cell count (OR = 0.995, 95% CI 0.992-0.998) and water treatment (OR = 0.231, 95% CI 0.126-0.830) were associated with a lower risk of diarrhoea, while close contact with cows (OR = 3.200, 95% CI 1.26-8.13) or pigs (OR = 11.176, 95% CI 3.76-43.56) were associated with a higher risk of diarrhoea.

CONCLUSIONS

Multiple enteric pathogens that are causative agents of diarrhoea were isolated from stools of antiretroviral therapy-naïve HIV/AIDS patients, indicating a need for surveillance, treatment and promotion of hygienic practices.

Epidemiology of intestinal polyparasitism among Orang Asli school children in rural Malaysia

Background

This cross-sectional study aimed to investigate the current prevalence and risk factors associated with intestinal polyparasitism (the concurrent infection with multiple intestinal parasite species) among Orang Asli school children in the Lipis district of Pahang state, Malaysia.

Methods/Principal findings

Fecal samples were collected from 498 school children (50.6% boys and 49.4% girls), and examined by using direct smear, formalin-ether sedimentation, trichrome stain, modified Ziehl Neelsen stain, Kato-Katz, and Harada Mori techniques. Demographic, socioeconomic, environmental, and personal hygiene information were collected by using a pre-tested questionnaire. Overall, 98.4% of the children were found to be infected by at least one parasite species. Of these, 71.4% had polyparasitism. The overall prevalence of Trichuris trichiura, Ascaris lumbricoides, hookworm, Giardia duodenalis, Entamoeba spp., and Cryptosporidium spp. infections were 95.6%, 47.8%, 28.3%, 28.3%, 14.1% and 5.2%, respectively. Univariate and multivariate analyses showed that using an unsafe water supply as a source for drinking water, presence of other family members infected with intestinal parasitic infections (IPI), not washing vegetables before consumption, absence of a toilet in the house, not wearing shoes when outside, not cutting nails periodically, and not washing hands before eating were significant risk factors associated with intestinal polyparasitism among these children.

Conclusions/Significance

Intestinal polyparasitism is highly prevalent among children in the peninsular Malaysian Aboriginal communities. Hence, effective and sustainable control measures, including school-based periodic chemotherapy, providing adequate health education focused on good personal hygiene practices and proper sanitation, as well as safe drinking water supply should be implemented to reduce the prevalence and consequences of these infections in this population.

Intestinal parasitic infections (IPI) are still a major public health problem worldwide, with more than 2 billion people infected with at least one parasite species. Despite efforts to improve the quality of life of the Orang Asli population in rural Malaysia, IPI are still highly prevalent and of serious concern in this population, especially among children. We screened 498 school children in Lipis district, Pahang, Malaysia for the prevalence and risk factors of polyparasitism (concurrent infection with multiple parasite species). Overall, 98.4% of the children were found to be infected by at least one parasite species, with 71.4% of them having polyparasitism. Using an unsafe water supply as a source for drinking water, presence of another family member infected with IPI, not washing vegetables before consumption, absence of a toilet in the house, not wearing shoes when outside, not cutting nails periodically, and not washing hands before eating were significantly associated with intestinal polyparasitism among these children. Our findings revealed an urgent need to implement an effective and integrated control program to reduce the prevalence of IPI as a part of the efforts to improve the quality of life in Orang Asli communities.

Should we look for Strongyloides stercoralis in foreign-born HIV-infected persons?

The objective was to evaluate the implementation of a systematic Strongyloides stercoralis screening programme in HIV infected immigrants attending an HIV Unit in Spain. An enzyme-linked immunosorbent assay (ELISA) was performed to assess the presence of Strongyloides IgG. Patients with a positive serology were treated with ivermectin; serologic follow-up testing was performed. 237 patients were screened (65.4 % men). Origin: 64.1 % came from Latin America, 16.5 % from Sub-Saharan Africa, 9.7 % from the Caribbean, 9.7 % from other areas. Strongyloides stercolaris IgG was positive in 13 cases (5.5 %). In the multivariate analysis, factors associated with a positive Strongyloides serology were illiteracy (OR: 23.31; p = 0.009) and eosinophilia (OR: 15.44; p < 0.0001). Nine of the 13 patients positive for S. stercoralis IgG and treated with ivermectin had a follow up serologic test: 77.8 % achieved a serologic response (55.5 % seroreversion). Screening of HIV-positive immigrants may be desirable, at least in those with higher risk of hyperinfection syndrome. Serologic testing seems a useful tool in both diagnosis and follow-up of these patients.

Cystic echinococcosis in a single tertiary care center in Rome, Italy

Background. Cystic echinococcosis (CE) is a chronic, clinically complex, and neglected disease. Its prevalence in Italy, a country of medium to high endemicity, remains poorly defined, as notification has long ceased to be mandatory. Methods. We set up a retrospective cohort study involving all CE patients followed at our institute between January 2005 and December 2012. Demographical and clinical features were recorded and analyzed. Results. CE was found in 28 patients (64.3%), mostly Italians from the central regions (50%), followed by subjects from the islands (33.3%) and Southern Italy (16.7%). Their median age was 45 years (IQR: 38.5–66.5), with Eastern Europeans being significantly younger (28 years, IQR: 19–39) than other patients (P ≤ 0.0001). A total of 149 cysts, mostly with hepatic localization (96%), were described. Based on the WHO classification, the cysts were mainly small (80.5%) and active (CE1 (73.8%); CE2 (7.4%)). Active cysts were more common in Eastern Europeans (85.7%) than Italians (66.7%). Conclusion. Our data confirm CE occurrence in Italy. We emphasize the importance to have a national CE registry, opportunely recently introduced. This is essential to assess CE prevalence in this country, implement appropriate control measures, and improve patient management.

HIV and intestinal parasite co-infections among a Chinese population: an immunological profile

BACKGROUND

Parasite infections often result in a switch of the human body's predominant immune reaction from T-helper 1 (Th1)-type to Th2-type. Hence, parasite infections are widely expected to accelerate the progression of human immunodeficiency virus (HIV) infections to acquired immunodeficiency syndrome (AIDS). In the People's Republic of China, both parasitic diseases and AIDS are epidemic in certain rural areas, and co-infections are relatively common. However, no population-based studies have yet investigated the frequency of HIV and parasite co-infections, and its effects on immune responses. We studied (1) the immune status of an HIV-infected population, and (2) the effect of co-infection of HIV and intestinal parasites on selected parameters of the human immune system.

METHODS

A total of 309 HIV-infected individuals were recruited and compared to an age-matched and sex-matched control group of 315 local HIV-negative individuals. Questionnaires were administered to all participants to obtain information on sociodemographic characteristics, sanitation habits, family income, and recent clinical manifestations. Two consecutive stool samples and 10 ml samples of venous blood were also collected from each individual for the diagnosis of parasite infections and quantitative measurements of selected cytokines and CD4+ T-lymphocytes, respectively.

RESULTS

During the study period, 79 HIV-infected individuals were not under highly active antiretroviral therapy (HAART) and were thus included in our analysis; the prevalence of intestinal helminth infections was 6.3% and that of protozoa was 22.8%. The most common protozoan infections were Blastocystis hominis (B. hominis) (13.9%) and Cryptosporidium spp. (10.1%). The prevalence of Cryptosporidium spp. in HIV-infected individuals was significantly higher than that in HIV negative individuals (P < 0.05). Compared to the non-co-infected population, no significant difference was found for any of the measured immunological indicators (P > 0.05). However, the following trends were observed: IFN-γ levels were lower, but the IL-4 level was higher, in the population co-infected with HIV and helminths. In the population co-infected with HIV and B. hominis, the IL-2 level was higher. The population co-infected with HIV and Cryptosporidium spp. had markedly lower CD4+ T-lymphocyte counts.

CONCLUSION

According to the immunologic profile, co-infection with helminths is disadvantageous to HIV-infected individuals. It was associated with a shift in the Th1/Th2 balance in the same direction as that caused by the virus itself, which might indicate an acceleration of the progress from an HIV infection to AIDS. Co-infection with Cryptosporidium spp. was not associated with a significant change in immune factors but co-infection with Cryptosporidium spp. was associated with a reduced level of CD4 + T-lymphocytes, confirming the opportunistic nature of such infections. Co-infection with B. hominis, on the other hand, was associated with an antagonistic shift in the immunological profile compared to an HIV infection.

Mycoplasmas infection in male HIV/AIDS patients in Jiangsu, China

Mycoplasmas are widely distributed among animals, plants, and human. The four species namely, Mycoplasmas genitalium(Mg), Mycoplasmas fermentans(Mf), Mycoplasmas pentrans(Mpe), Mycoplasmas pirum(Mpi) are also called AIDS-associated mycoplasmas due to their involvement in the development and outcome of AIDS. To investigate the infection prevalence of Mg, Mf, Mpe and Mpi among male HIV/AIDS patients in Jiangsu Province and to analyze the relationship between pathogenic mycoplasmas and cellular immune function of them. First void urine and venous blood samples were collected and epidemiology questionnaires were administered after informed consent. Nested PCR was performed to determine the infection of Mg, Mf, Mpe and Mpi while ELISA assay was applied to detect interleukin-2(IL-2), interferon-γ(IFN-γ) and tumor necrosis factor-α(TNF-α). SAS 9.0 software was applied to analyze the data. A total of 713 HIV/AIDS patients were recruited in this study. The overall infection rates of Mg, Mf, Mpe and Mpi are 27.9%, 9.7%, 1.0% and 18.4% respectively. Generally, the infection rates of Mg(χ(2) = 10.311, P = 0.006) and Mpi were declined as the CD4+ cell counts increased, while Mf infection was higher in CD4+ T cell>350/μl group. The levels of cytokines are different with the variance of mycoplasmas infection. Mycoplasma infection among male HIV/AIDS patients is associated with changes in cellular immune response (cytokines). However, the affect of mycoplasmas on the immune function is complex, further studies are still required to elucidate whether mycoplasmas interact with HIV by interfering host immune system.

Tropical diseases screening in immigrant patients with human immunodeficiency virus infection in Spain

Latent parasitic infections can reactivate because of immunosuppression. We conducted a prospective observational study of all human immunodeficiency virus (HIV)-infected immigrants who visited the Infectious Diseases Department of the Hospital Universitari Vall d'Hebron, Barcelona, Spain, during June 2010-May 2011. Screening of the most prevalent tropical diseases (intestinal parasitosis, Chagas disease, leishmaniasis, malaria, schistosomiasis, and strongyloidiasis) was performed according to geographic origin. A total of 190 patients were included: 141 (74.2%) from Latin America, 41 (21.6%) from sub-Saharan Africa, and 8 (4.2%) from northern Africa. Overall, 36.8% (70 of 190) of the patients had at least one positive result for any parasitic disease: 5 patients with positive Trypanosoma cruzi serology, 11 patients with positive Schistosoma mansoni serology, 35 patients with positive Strongyloides stercoralis serology, 7 patients with positive Leishmania infantum serology, intestinal parasitosis were detected in 37 patients, malaria was diagnosed in one symptomatic patient. We propose a screening and management strategy of latent parasitic infections in immigrant patients infected with HIV.

Prevalence of Strongyloides stercoralis in an urban US AIDS cohort

OBJECTIVES

We examined the prevalence of Strongyloides stercoralis (Ss) infection in a cohort of AIDS patients from a US urban centre. We monitored our cohort for possible cases of dissemination or immune reconstitution inflammatory syndrome after antiretroviral therapy (ART) initiation.

METHODS

One hundred and three HIV-infected participants were prospectively sampled from a cohort observational study of ART-naive HIV-1-infected patients with CD4 ≤100 T cells/μl. Clinical symptoms, corticosteroid therapy, eosinophilia, CD4 count, and plasma HIV-RNA were reviewed. Sera were tested by an enzyme-linked immunosorbent assay (CrAg-ELISA) to crude Ss extract or to an Ss-specific recombinant protein (NIE) and by luciferase immunoprecipitation system assay (LIPS) for Ss-specific antibodies.

RESULTS

Twenty-five per cent of study participants were Strongyloides seropositive by CrAg-ELISA and 62% had emigrated from Strongyloides-endemic areas. The remaining 38% of the seropositives were US born and tested negative by NIE and LIPS. CrAg-ELISA-positive participants had a median CD4 count of 22 T cells/μl and a median HIV-RNA of 4·87 log(10) copies/ml. They presented with diarrhea (27%), abdominal pain (23%), and skin manifestations (35%) that did not differ from seronegative patients. Peripheral blood eosinophilia was common among seropositive patients (prevalence of 62% compared to 29% in seronegatives, P = 0·004). Seropositive patients were treated with ivermectin. There were no cases of hyperinfection syndrome.

DISCUSSION

Strongyloidiasis may be prevalent in AIDS patients in the USA who emigrated from Ss-endemic countries, but serology can be inconclusive, suggesting that empiric ivermectin therapy is a reasonable approach in AIDS patients originating from Strongyloides endemic areas.

Systemic mycoses in immunodepressed patients (AIDS)

Infectious and noninfectious skin diseases are observed in about 90% of HIV patients, and their incidence increases and is more severe as the immune system weakens. Cutaneous manifestations are considered good clinical predictors for the immunological condition of the patient with AIDS and the introduction of highly effective antiretroviral therapy totally changed the prognosis of the mycoses, among other diseases associated with AIDS, permitting longer survival and acceptable level of quality of life for these patients. This contribution describes the systemic mycoses that are more frequent in the seropositive population, that is, patients with HIV/AIDS, which are cryptococcosis, histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, sporotrichosis, penicilliosis, and aspergillosis. Their causative agents, mode of transmission, clinics, laboratorial diagnosis and therapy, in the aspects related to immunodepressed patients, are reviewed.

Within-host competition and diversification of macro-parasites

Although competitive speciation is more and more regarded as a plausible mechanism for sympatric speciation of non-parasite species, virtually no empirical or theoretical study has considered this evolutionary process to explain intra-host diversification of parasites. We expanded the theory of competitive speciation to parasite species looking at the effect of macro-parasite life history on the conditions for sympatric speciation under the so-called pleiotropic scenario. We included within-host competition in the classical Anderson and May framework assuming that individuals exploit within-host resources according to a quantitative trait. We derived the invasion fitness function of mutants considering different distributions of individuals among hosts. Although the mutant fitness depends on parameters describing the key features of macro-parasite life history, and on the relative distributions of mutant and residents in hosts, the conditions for competitive speciation of macro-parasites are exactly the same as those previously established for free-living species. As an interesting by-product, within-host competitive speciation is expected not to depend on the aggregation level of the parasites. This theoretical pattern is confirmed by comparing the speciation rate of weakly and strongly aggregated monogenean parasites.

Co-infection of HIV and tropical infectious agents that affect the nervous system

Tropical infections refer to a group of diseases usually located in regions with a warm climate, particularly affecting developing countries, partly because of the conditions that allow them to thrive. However, due to the increased international travel, infectious agents that were previously limited to tropical regions pose an increasing threat to populations at risk for opportunistic infection (OI), especially those infected with the HIV. Tropical infections can facilitate HIV transmission and accelerate the progression of asymptomatic HIV infection to AIDS. Some have the potential to alter the epidemiology, natural history, and/or response to treatment of the other. The introduction of highly active antiretroviral therapy has provided a huge benefit for the vast majority of patients infected with the HIV, by allowing the immune system to recover, improving the clinical and radiological results and reducing the number of OI. On the other hand, some patients have developed various disorders of immune reconstitution, resulting in either hyper-immune inflammatory response to an exogenous antigen or autoimmunity. A significant proportion of these cases have been reported in immigrants from tropical countries to high-income countries, therefore awareness of these phenomena is needed since clinical presentations are often atypical and pose diagnostic challenges. This article reviews some of the key diagnostic aspects of tropical infections associated with HIV infection.

Co-infection of HIV and intestinal parasites in rural area of China

BACKGROUND

Intestinal parasite infections (IPIs) are among the most significant causes of illness and disease of socially and economically disadvantaged populations in developing countries, including rural areas of the People's Republic of China. With the spread of the human immunodeficiency virus (HIV) among rural Chinese populations, there is ample scope for co-infections and there have been increasing fears about their effects. However, hardly any relevant epidemiological studies have been carried out in the country. The aim of the present survey was to assess the IPI infection status among a representative sample of HIV-positive Chinese in rural Anhui province, and compare the findings with those from a cohort of non-infected individuals.

METHODS

A case control study was carried out in a rural village of Fuyang, Anhui province, China. Stool samples of all participants were examined for the presence of intestinal parasites. Blood examination was performed for the HIV infection detection and anemia test. A questionnaire was administered to all study participants.

RESULTS

A total of 302 HIV positive and 303 HIV negative individuals provided one stool sample for examination. The overall IPI prevalence of intestinal helminth infections among HIV positives was 4.3% (13/302) while it was 5.6% (17/303) among HIV negatives, a non-significant difference. The prevalence of protozoa infections among HIV positives was 23.2% while the rate was 25.8% among HIV negatives. The species-specific prevalences among HIV positives were as follows: 3.6% for hookworm, 0.7% for Trichuris trichiura, zero for Ascaris lumbricoides, 0.3% for Clonorchis sinensis, 1.3% for Giardia intestinalis, 16.2% for Blastocystis hominis, 1.7% for Entamoeba spp. and 8.3% for Cryptosporidium spp.. Cryptosporidium spp. infections were significantly more prevalent among HIV positives (8.3%) compared to the HIV negative group (3.0%; P < 0.05). Among people infected with HIV, Cryptosporidium spp. was significantly more prevalent among males (12.6%) than females (4.4%; P < 0.05). According to multivariate logistic regression, the factors significantly associated with parasite infections of the people who were HIV positive included sex (male: OR = 6.70, 95% CI: 2.030, 22.114), younger age (less than 42 years old: OR = 4.148, 95% CI: 1.348, 12.761), and poor personal hygiene habits (OR = 0.324, 95% CI: 0.105, 0.994).

CONCLUSIONS

HIV positive individuals are more susceptible to co-infections with Cryptosporidium spp. than HIV negative people, particularly younger males with poor personal hygiene habits, indicating a need for targeted hygiene promotion, IPI surveillance and treatment.

Bifidobacterial surface-exopolysaccharide facilitates commensal-host interaction through immune modulation and pathogen protection

Bifidobacteria comprise a significant proportion of the human gut microbiota. Several bifidobacterial strains are currently used as therapeutic interventions, claiming various health benefits by acting as probiotics. However, the precise mechanisms by which they maintain habitation within their host and consequently provide these benefits are not fully understood. Here we show that Bifidobacterium breve UCC2003 produces a cell surface-associated exopolysaccharide (EPS), the biosynthesis of which is directed by either half of a bidirectional gene cluster, thus leading to production of one of two possible EPSs. Alternate transcription of the two opposing halves of this cluster appears to be the result of promoter reorientation. Surface EPS provided stress tolerance and promoted in vivo persistence, but not initial colonization. Marked differences were observed in host immune response: strains producing surface EPS (EPS(+)) failed to elicit a strong immune response compared with EPS-deficient variants. Specifically, EPS production was shown to be linked to the evasion of adaptive B-cell responses. Furthermore, presence of EPS(+) B. breve reduced colonization levels of the gut pathogen Citrobacter rodentium. Our data thus assigns a pivotal and beneficial role for EPS in modulating various aspects of bifidobacterial-host interaction, including the ability of commensal bacteria to remain immunologically silent and in turn provide pathogen protection. This finding enforces the probiotic concept and provides mechanistic insights into health-promoting benefits for both animal and human hosts.

From host immunity to pathogen invasion: the effects of helminth coinfection on the dynamics of microparasites

Concurrent infections with multiple parasites are ubiquitous in nature. Coinfecting parasites can interact with one another in a variety of ways, including through the host's immune system via mechanisms such as immune trade-offs and immunosuppression. These within-host immune processes mediating interactions among parasites have been described in detail, but how they scale up to determine disease dynamic patterns at the population level is only beginning to be explored. In this review, we use helminth-microparasite coinfection as a model for examining how within-host immunological effects may influence the ecological outcome of microparasitic diseases, with a specific focus on disease invasion. The current literature on coinfection between helminths and major microparasitic diseases includes many studies documenting the effects of helminths on individual host responses to microparasites. In many cases, the observed host responses map directly onto parameters relevant for quantifying disease dynamics; however, there have been few attempts at integrating data on individual-level effects into theoretical models to extrapolate from the individual to the population level. Moreover, there is considerable variability in the particular combination of disease parameters affected by helminths across different microparasite systems. We develop a conceptual framework identifying some potential sources of such variability: Pathogen persistence and severity, and resource availability to hosts. We also generate testable hypotheses regarding diseases and the environmental contexts when the effects of helminths on microparasite dynamics should be most pronounced. Finally, we use a case study of helminth and mycobacterial coinfection in the African buffalo to illustrate both progress and challenges in understanding the population-level consequences of within-host immunological interactions, and conclude with suggestions for future research that will help improve our understanding of the effects of coinfection on dynamics of infectious diseases.

Concurrency revisited: increasing and compelling epidemiological evidence

Multiple sexual partnerships must necessarily lie at the root of a sexually transmitted epidemic. However, that overlapping or concurrent partnerships have played a pivotal role in the generalized epidemics of sub-Saharan Africa has been challenged. Much of the original proposition that concurrent partnerships play such a role focused on modelling, self-reported sexual behaviour data and ethnographic data. While each of these has definite merit, each also has had methodological limitations. Actually, more recent cross-national sexual behaviour data and improved modelling have strengthened these lines of evidence. However, heretofore the epidemiologic evidence has not been systematically brought to bear. Though assessing the epidemiologic evidence regarding concurrency has its challenges, a careful examination, especially of those studies that have assessed HIV incidence, clearly indicates a key role for concurrency.Such evidence includes: 1) the early and dramatic rise of HIV infection in generalized epidemics that can only arise from transmission through rapid sequential acute infections and thereby concurrency; 2) clear evidence from incidence studies that a major portion of transmission in the population occurs via concurrency both for concordant negative and discordant couples; 3) elevation in risk associated with partner's multiple partnering; 4) declines in HIV associated with declines in concurrency; 5) bursts and clustering of incident infections that indicate concurrency and acute infection play a key role in the propagation of epidemics; and 6) a lack of other plausible explanations, including serial monogamy and non-sexual transmission. While other factors, such as sexually transmitted infections, other infectious diseases, biological factors and HIV sub-type, likely play a role in enhancing transmission, it appears most plausible that these would amplify the role of concurrency rather than alter it. Additionally, critics of concurrency have not proposed plausible alternative explanations for why the explosive generalized epidemics occurred. Specific behaviour change messaging bringing the concepts of multiple partnering and concurrency together appears salient and valid in promoting safer individual behaviour and positive social norms.

Evaluation of the effect of pyrimethamine, an anti-malarial drug, on HIV-1 replication

Co-infection of human immunodeficiency virus (HIV) with malaria is one of the pandemic problems in Africa and parts of Asia. Here we investigated the impact of pyrimethamine (PYR) and two other clinical anti-malarial drugs (chloroquine [CQ] or artemisinin [ART]) on HIV-1 replication. Peripheral blood mononuclear cells (PBMCs) or MT-2 cells were infected with HIV(NL4.3) strain and treated with different concentrations of the anti-malarial drugs. HIV-1 replication was measured using p24 ELISA. We show that 10 μM CQ and ART inhibited HIV-1 replication by 76% and 60% in PBMCs, respectively, but not in MT-2 cells. In contrast, 10 μM PYR enhanced HIV-1 replication in MT-2 cells by >10-fold. A series of molecular mechanism studies revealed that PYR increased intracellular HIV gag proteins without affecting the promoter or the reverse transcriptase activity. The effect of PYR was independent of HTLV-1 produced by MT-2 cells. Of interest, PYR treatment led to S-phase accumulation and increased AZT and d4T antiviral activity by ∼ 4-fold. Taken together, we show that PYR significantly enhances HIV-1 replication by affecting the cellular machinery. Our results could be relevant for the management of malaria and HIV particularly in regions where HIV-1 and malaria epidemics overlap.

Contrasting roles for TLR ligands in HIV-1 pathogenesis

The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs). Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs) 5 and 9, we examined their effect on human immunodeficiency virus (HIV)-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist) treatment enhanced replication of CC chemokine receptor 5 (CCR 5)-tropic and CXC chemokine receptor 4 (CXCR4)-tropic HIV-1, treatment with oligodeoxynucleotide (ODN) M362 (TLR9 agonist) suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD) 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA)-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention.

Elevated plasma levels of lipopolysaccharide and high mobility group box-1 protein are associated with high viral load in HIV-1 infection: reduction by 2-year antiretroviral therapy

OBJECTIVE

To investigate plasma levels of high mobility group box-1 protein (HMGB1), a marker of tissue necrosis and immune activation, as well as lipopolysaccharide (LPS), a marker of bacterial translocation, in HIV-1-infected patients.

DESIGN

We studied 32 HIV-1-positive patients who had responded to antiretroviral therapy with undetectable viremia after 2 years, 10 nonresponders and 19 healthy controls.

METHODS

HMGB1 was analyzed by ELISA, and LPS by Lamilus colometric assay. Nonparametric statistics were applied.

RESULTS

In naive HIV-1 patients, HMGB1 and LPS were elevated as compared with controls (P < 0.001). LPS levels were higher in African and Oriental patients compared with whites (P = 0.007). Notably, viral load was two-fold higher in patients with LPS, and HMGB1 was above median as compared with other patients (P = 0.005). This association was largely driven by African patients, who had a five-fold increased viral load in the presence of elevated LPS and HMGB1. After 2 years of effective antiretroviral therapy, LPS was reduced to the same median level as in the control group (P < 0.001), and HMGB1 was also reduced (P = 0.001), whereas no reductions were seen in nonresponders.

CONCLUSION

The new findings are the association of elevated plasma levels of LPS and HMGB1 with high viral load, as well as the normalized levels of LPS, and the reduction of HMGB1 after 2 years of effective antiretroviral therapy. As LPS and HMGB1 tend to form immunologically active complexes in vitro, we propose that such complexes may be involved in the immune activation and pathogenesis of HIV-1 infection.

Co-infection with paracoccidioidomycosis and human immunodeficiency virus: report of a case with esophageal involvement

Paracoccidioiodomycosis (PCM) is a systemic and deep mycosis endemic in Latin America, especially in Brazil. In patients infected with human immunodeficiency virus (HIV), PCM can manifest with prominent involvement of the reticuloendothelial system. There are no reports in the literature of esophageal involvement by PCM in that population. We report a case of PCM with pulmonary and esophageal involvement without radiologic evidence of an esophageal-bronchial fistula in an HIV-infected patient.