Treatment of intestinal worms is associated with decreased HIV plasma viral load

Prevalence of soil-transmitted helminth infections in HIV patients: a systematic review and meta-analysis

Soil-transmitted Helminth (STH) infections have been found associated with people living with human immunodeficiency virus (HIV) but little is known about the overall burden of STH coinfection in HIV patients. We aimed to assess the burden of STH infections among HIV patients. Relevant databases were systematically searched for studies reporting the prevalence of soil-transmitted helminthic pathogens in HIV patients. Pooled estimates of each helminthic infection were calculated. The odds ratio was also determined as a measure of the association between STH infection and the HIV status of the patients. Sixty-one studies were finally included in the meta-analysis, consisting of 16,203 human subjects from all over the world. The prevalence of Ascaris lumbricoides infection in HIV patients was found to be 8% (95% CI 0.06, 0.09), the prevalence of Trichuris trichiura infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), the prevalence of hookworm infection in HIV patients was found to be 5% (95% CI 0.04, 0.06), and prevalence of Strongyloides stercoralis infection in HIV patients was found to be 5% (95% CI 0.04, 0.05). Countries from Sub-Saharan Africa, Latin America & Caribbean and Asia were identified with the highest burden of STH-HIV coinfection. Our analysis indicated that people living with HIV have a higher chance of developing Strongyloides stercoralis infections and decreased odds of developing hookworm infections. Our findings suggest a moderate level of prevalence of STH infections among people living with HIV. The endemicity of STH infections and HIV status both are partially responsible for the burden of STH-HIV coinfections.

Hookworm Infections and Sociodemographic Factors Associated With Female Reproductive Tract Infections in Rural Areas of the Central Region of Togo

Female reproductive tract infections (FRTIs) have a huge impact on women’s health including their reproductive health in rural areas. Immunomodulation by helminth infections could influence the occurrence of FRTIs. This study aimed to investigate the association between FRTIs, hookworm infections, and sociodemographic factors in six rural areas of the central region of Togo. A semi-structured questionnaire was used to collect sociodemographical information, and parasitological assessments were used to diagnose helminth infections. Moreover, cytobacteriological examination of vaginal swabs was performed for the diagnosis of candidiasis and bacterial vaginosis (BV), and real-time PCR method was used to determine sexually transmitted infections (STIs). Finally, a logistic regression analysis was performed to assess the relationship and association of these factors to FRTIs. The prevalence of FRTIs was 82.3% including STIs (74.38%), BV (31.79%), and vulvovaginal candidiasis (9.85%). In detail, FRTIs were caused by bacteria such as Ureaplasma parvum (50%), Ureaplasma urealyticum (26.5%), and Mycoplasma hominis (17.5%) and viruses such us cytomegalovirus (5%) and human papilloma virus (HPV) (20%). No cases of Haemophilus ducreyi, Treponema pallidum, or varicella-zoster virus (VZV) were observed. Interestingly, women who had hookworm infections were at high risk of HPV. The use of condoms was a protective factor [adjusted odds ratio (aOR) = 0.23; 95% CI [0.11–0.51)], while the use of contraceptive methods was a risk factor [aOR = 2.49; 95% CI (1.19–5.19)] for STIs. The risk of BV was lower among participants who had more than four pregnancies [aOR = 0.27; 95% CI (0.11–0.65)]. Furthermore, women who had ever been paid for sexual intercourse were at high probability risk of vulvovaginal candidiasis [aOR = 16.92; 95% CI (1.46–196.48)]. This study highlighted risk factors associated with FRTIs, the control of which would help to reduce the incidence of these diseases. Health-care professionals could develop education and sensitization strategies based on these risk factors, and anti-hookworm treatment concepts may be taken into consideration to minimize the risk of HPV infections.

Chronic Immune Activation and CD4+ T Cell Lymphopenia in Healthy African Individuals: Perspectives for SARS-CoV-2 Vaccine Efficacy

Chronic immune activation has been considered as the driving force for CD4+ T cell depletion in people infected with HIV-1. Interestingly, the normal immune profile of adult HIV-negative individuals living in Africa also exhibit chronic immune activation, reminiscent of that observed in HIV-1 infected individuals. It is characterized by increased levels of soluble immune activation markers, such as the cytokines interleukin (IL)-4, IL-10, TNF-α, and cellular activation markers including HLA-DR, CD-38, CCR5, coupled with reduced naïve and increased memory cells in CD4+ and CD8+ subsets. In addition, it is accompanied by low CD4+ T cell counts when compared to Europeans. There is also evidence that mononuclear cells from African infants secrete less innate cytokines than South and North Americans and Europeans in vitro. Chronic immune activation in Africans is linked to environmental factors such as parasitic infections and could be responsible for previously observed immune hypo-responsiveness to infections and vaccines. It is unclear whether the immunogenicity and effectiveness of anti-SARS-CoV-2 vaccines will also be reduced by similar mechanisms. A review of studies investigating this phenomenon is urgently required as they should inform the design and delivery for vaccines to be used in African populations.

Impact of Helminth Infections on Female Reproductive Health and Associated Diseases

A growing body of knowledge exists on the influence of helminth infections on allergies and unrelated infections in the lung and gastrointestinal (GI) mucosa. However, the bystander effects of helminth infections on the female genital mucosa and reproductive health is understudied but important considering the high prevalence of helminth exposure and sexually transmitted infections in low- and middle-income countries (LMICs). In this review, we explore current knowledge about the direct and systemic effects of helminth infections on unrelated diseases. We summarize host disease-controlling immunity of important sexually transmitted infections and introduce the limited knowledge of how helminths infections directly cause pathology to female reproductive tract (FRT), alter susceptibility to sexually transmitted infections and reproduction. We also review work by others on type 2 immunity in the FRT and hypothesize how these insights may guide future work to help understand how helminths alter FRT health.

Schistosoma and Strongyloides screening in migrants initiating HIV Care in Canada: a cross sectional study

BACKGROUND

Following migration from Schistosoma and Strongyloides endemic to non-endemic regions, people remain at high risk for adverse sequelae from these chronic infections. HIV co-infected persons are particularly vulnerable to the serious and potentially fatal consequences of untreated helminth infection. While general screening guidelines exist for parasitic infection screening in immigrant populations, they remain silent on HIV positive populations. This study assessed the seroprevalence, epidemiology and laboratory characteristics of these two parasitic infections in a non-endemic setting in an immigrant/refugee HIV positive community.

METHODS

Between February 2015 and 2018 individuals born outside of Canada receiving care at the centralized HIV clinic serving southern Alberta, Canada were screened by serology and direct stool analysis for schistosomiasis and strongyloidiasis. Canadian born persons with travel-based exposure risk factors were also screened. Epidemiologic and laboratory values were analyzed using bivariate logistic regression. We assessed the screening utility of serology, direct stool analysis, eosinophilia and hematuria.

RESULTS

253 HIV positive participants were screened. The prevalence of positive serology for Schistosoma and Strongyloides was 19.9 and 4.4%, respectively. Age between 40 and 50 years (OR 2.50, 95% CI 1.13-5.50), refugee status (3.55, 1.72-7.33), country of origin within Africa (6.15, 2.44-18.60), eosinophilia (3.56, 1.25-10.16) and CD4 count < 200 cells/mm3 (2.46, 1.02-5.92) were associated with positive Schistosoma serology. Eosinophilia (11.31, 2.03-58.94) was associated with positive Strongyloides serology. No Schistosoma or Strongyloides parasites were identified by direct stool microscopy. Eosinophilia had poor sensitivity for identification of positive serology. Hematuria was not associated with positive Schistosoma serology.

CONCLUSION

Positive Schistosoma and Strongyloides serology was common in this migrant HIV positive population receiving HIV care in Southern Alberta. This supports the value of routine parasitic screening as part of standard HIV care in non-endemic areas. Given the high morbidity and mortality in this relatively immunosuppressed population, especially for Strongyloides infection, screening should include both serologic and direct parasitological tests. Eosinophilia and hematuria should not be used for Schistosoma and Strongyloides serologic screening in HIV positive migrants in non-endemic settings.

Schistosoma mansoni soluble egg antigen (SEA) and recombinant Omega-1 modulate induced CD4+ T-lymphocyte responses and HIV-1 infection in vitro

Parasitic helminths evade, skew and dampen human immune responses through numerous mechanisms. Such effects will likely have consequences for HIV-1 transmission and disease progression. Here we analyzed the effects that soluble egg antigen (SEA) from Schistosoma mansoni had on modulating HIV-1 infection and cytokine/chemokine production in vitro. We determined that SEA, specifically through kappa-5, can potently bind to DC-SIGN and thereby blocks DC-SIGN mediated HIV-1 trans-infection (p<0.05) whilst not interfering with cis-infection. DCs exposed to SEA whilst maturing under Th2 promoting conditions, will upon co-culture with naïve T-cells induce a T-cell population that was less susceptible to HIV-1 R5 infection (p<0.05) compared to DCs unexposed to SEA, whereas HIV-1 X4 virus infection was unaffected. This was not observed for DCs exposed to SEA while maturing under Th1 or Th1/Th2 (T_mix) promoting conditions. All T-cell populations induced by SEA exposed DCs demonstrate a reduced capacity to produce IFN-γ and MIP-1β. The infection profile of T-cells infected with HIV-1 R5 was not associated with down-modulation of CCR5 cell surface expression. We further show that DCs maturing under T_mix conditions exposed to plant recombinant omega-1 protein (rω-1), which demonstrates similar functions to natural ω-1, induced T-cell populations that were less sensitive for HIV-1 R5 infection (p<0.05), but not for X4 virus infection. This inhibition associated again with a reduction in IFN-γ and MIP-1β expression, but additionally correlated with reduced CCR5 expression. We have shown that SEA parasite antigens and more specifically rω-1 can modulate HIV-1 infectivity with the potential to influence disease course in co-infected individuals.

Parasitic helminths have developed a number of strategies to evade, skew and dampen human immune responses. Such effects will likely have consequences for HIV-1 transmission and disease progression. Here we analyzed the effect that soluble egg antigen (SEA) from Schistosoma mansoni had on HIV-1 infection in vitro. We determined that SEA, through kappa-5, can potently block DC-SIGN mediated HIV-1 trans-infection of CD4⁺ T-lymphocytes, but not block cis-infection. Dendritic cells (DC) exposed to SEA during maturation under Th2 skewing conditions, induce T-cell populations that are less susceptible to HIV-1 R5 infection compared to cells induced by unexposed DCs. HIV-1 X4 infection was unaffected. This restricted infection profile was not associated with down-modulation of CCR5 surface expression or observed differences in cytokine/chemokine production. Using recombinant omega-1, an abundant component of SEA, HIV-1 R5 infection was similarly inhibited with no effect on HIV-1 X4 infection levels. Hence SEA possesses antigens, namely omega-1, that can modulate HIV-1 infection and potentially influence disease course in co-infected individuals.

van Dam G, Corstjens PL, Hughes P, Ding S, Pantaleo G, Kaleebu P, Elliott AM, Kamali A. Effect of high-intensity versus low-intensity praziquantel treatment on HIV disease progression in HIV and Schistosoma mansoni co-infected patients: a randomised controlled trial

Background: It has been hypothesised that Schistosoma co-infection exacerbates HIV progression, and hence anthelminthic intervention in co-infected individuals will delay it. We evaluated effects of high-intensity versus low-intensity praziquantel treatment of schistosomiasis on HIV disease progression among co-infected patients from fishing populations around Lake Victoria, Uganda. Methods: Between August 2012 and September 2015, we conducted an open-label randomised, controlled trial. Adults, antiretroviral therapy-naïve, CD4 counts ≥350 cells/μl, HIV and S. mansoni co-infected, were randomised 1:1 to praziquantel (40mg/kg) given quarterly (starting at enrolment) or annually (starting 12 weeks after enrolment; such that low-intensity participants were still untreated when sampled at 12 weeks). A non-randomised HIV-positive S. mansoni-negative comparison group was recruited. The primary outcome was mean change in plasma viral load at 12 and 60 weeks. Results: In total 363 participants (high-intensity 113, low-intensity 113, comparison group 137) were recruited; 96 (85.0%), 97 (85.8%) and 107 (78.1%) completed 60 weeks of follow up, respectively. Adjusting for baseline age and viral load, the geometric mean ratio (aGMR [95%CI]) viral load for high-intensity vs low-intensity groups at 12 weeks was 0.90 [0.65, 1.25] p=0.55 and at 60 weeks 1.88 [0.78, 4.53] p=0.16. Results in the comparison group were similar to trial arms. High-intensity, compared to low-intensity, treatment resulted in substantially lower S. mansoni prevalence at all follow up visits (p<0.05). Conclusions: In communities with a high burden of both S. mansoni and HIV infection, high-intensity treatment of S. mansoni does not delay HIV progression despite relevant benefit for parasite clearance. Trial registration: ISRCTN15371662 (17/11/2016).

van Dam G, Corstjens PL, Hughes P, Ding S, Pantaleo G, Kaleebu P, Elliott AM, Kamali A. Effect of high-intensity versus low-intensity praziquantel treatment on HIV disease progression in HIV and Schistosoma mansoni co-infected patients: a randomised controlled trial

Background: It has been hypothesised that Schistosoma co-infection exacerbates HIV progression, and hence anthelminthic intervention in co-infected individuals will delay it. We evaluated effects of high-intensity versus low-intensity praziquantel treatment of schistosomiasis on HIV disease progression among co-infected patients from fishing populations around Lake Victoria, Uganda. Methods: Between August 2012 and September 2015, we conducted an open-label randomised, controlled trial. Adults, antiretroviral therapy-naïve, CD4 counts ≥350 cells/μl, HIV and S. mansoni co-infected, were randomised 1:1 to praziquantel (40mg/kg) given quarterly (starting at enrolment) or annually (starting 12 weeks after enrolment; such that low-intensity participants were still untreated when sampled at 12 weeks). A non-randomised HIV-positive S. mansoni-negative comparison group was recruited. The primary outcome was mean change in plasma viral load at 12 and 60 weeks. Results: In total 363 participants (high-intensity 113, low-intensity 113, comparison group 137) were recruited; 96 (85.0%), 97 (85.8%) and 107 (78.1%) completed 60 weeks of follow up, respectively. Adjusting for baseline age and viral load, the geometric mean ratio (aGMR [95%CI]) viral load for high-intensity vs low-intensity groups at 12 weeks was 0.90 [0.65, 1.25] p=0.55 and at 60 weeks 1.88 [0.78, 4.53] p=0.16. Results in the comparison group were similar to trial arms. High-intensity, compared to low-intensity, treatment resulted in substantially lower S. mansoni prevalence at all follow up visits (p<0.05). Conclusions: In communities with a high burden of both S. mansoni and HIV infection, high-intensity treatment of S. mansoni does not delay HIV progression despite relevant benefit for parasite clearance. Trial registration: ISRCTN15371662 (17/11/2016).

Effects of Helminth Eradication on the Immune System

Introduction:

Helminth infection has a profound effect on the immune system. However, the precise nature of the immune changes that are elicited by helminth infection have not been sufficiently characterized. Furthermore, the reversibility of these changes after treatment has not been documented sufficiently. We studied the immune profiles of Ethiopian immigrants to Israel at baseline, that is on arrival and at one-year follow-up and compared individuals who received antihelminth treatment during the study period with those who missed the treatment.

Methods:

A longitudinal follow up study involving different groups of subjects was conducted. Baseline data was recorded from the newly arrived Ethiopian immigrants for a series of peripheral blood tests, including: IgE and Eosinophil levels, T-cell populations, T-cell receptor phenotypes, and cytokine measurement. These tests were all repeated after a 1-year interval. Results were compared between the newly arrived Ethiopian immigrants (NEW-Eth-Il), long term Ethiopian immigrants (LT-Eth-Il), and non Ethiopian Israeli controls (NON-Imm-Il).

Results:

Of the 184 individuals, 111 were NEW-Eth-Il, who had a high prevalence of helminth infection, the immunological changes were elevated IgE levels and eosinophil counts, decreased CD4/CD8 ratio, increased proportion of HLA-DR+CD3+, HLA-DR+CD4+ and HLA-DR+CD8+ cells, decreased proportion of CD45RA+CD4+ (naive) and CD28+CD8+ cells, increased proportion of CD45RO+CD4+ (memory) cells, and increased secretion of IL-4 and IL-5 (Th2 type cytokines). In the 42 LT-Eth-Il participants, who all had negative tests for helminth infection, we did not observe these immune changes and their immune profile did not differ markedly from that of the NON-Imm-Il controls. The follow-up immune profiles of 33 NEW-Eth-Il who received succesful antihelminth treatment, showed a significant normalization in the above-mentioned variables that was not observed in the 19 NEW-Eth-Il who missed and did not receive the antihelminth treatment.

Conclusions:

These findings demonstrate that helminth infection is associated with profound immune changes that are normalized within a short time after helminth eradication. They also strengthen the hypothesis that effective antihelminth interventions, in areas endemic for intestinal helminths, may have an impact on AIDS and tuberculosis epidemics.

S. mansoni-T. cruzi co-infection modulates arginase-1/iNOS expression, liver and heart disease in mice

Although Schistosoma species and Trypanosoma cruzi share common endemic areas, co-infections by these parasites remains overlooked. By using a murine model of S. mansoni and T. cruzi co-infection, we investigated if and to what extent these infections might interact to change the pathological outcomes typically observed when the host is infected by a single parasite species. Swiss mice were randomized into four groups: uninfected (NI) and those infected by S. mansoni (SM), T. cruzi (TC) or co-infected (SM + TC). After 120 days of S. mansoni infection, T. cruzi was concurrently inoculated and the infection occurred for 30 days. Taken together, we identified that the overlap of Th2 (schistosomiasis) and Th1 (Chagas disease) immunological patterns changes the host resistance against both pathogens. Beyond impairing the control of granulomatous inflammation, T. cruzi parasitemia and parasitism in co-infected animals, the Th2 inflammatory response against S. mansoni elicits the activation of the arginase-1 pathway to the detriment of inducible oxide nitric synthase (iNOS) expression and nitric oxide (NO) production, contributing to the liver damage, with minor effects on heart pathology.

Filariae-Retrovirus Co-infection in Mice is Associated with Suppressed Virus-Specific IgG Immune Response and Higher Viral Loads

Worldwide more than 2 billion people are infected with helminths, predominantly in developing countries. Co-infections with viruses such as human immunodeficiency virus (HIV) are common due to the geographical overlap of these pathogens. Helminth and viral infections induce antagonistic cytokine responses in their hosts. Helminths shift the immune system to a type 2-dominated immune response, while viral infections skew the cytokine response towards a type 1 immune response. Moreover, chronic helminth infections are often associated with a generalized suppression of the immune system leading to prolonged parasite survival, and also to a reduced defence against unrelated pathogens. To test whether helminths affect the outcome of a viral infection we set up a filarial/retrovirus co-infection model in C57BL/6 mice. Although Friend virus (FV) infection altered the L. sigmodontis-specific immunoglobulin response towards a type I associated IgG2 isotype in co-infected mice, control of L. sigmodontis infection was not affected by a FV-superinfection. However, reciprocal control of FV infection was clearly impaired by concurrent L. sigmodontis infection. Spleen weight as an indicator of pathology and viral loads in spleen, lymph nodes (LN) and bone marrow (BM) were increased in L. sigmodontis/FV-co-infected mice compared to only FV-infected mice. Numbers of FV-specific CD8⁺ T cells as well as cytokine production by CD4⁺ and CD8⁺ cells were alike in co-infected and FV-infected mice. Increased viral loads in co-infected mice were associated with reduced titres of neutralising FV-specific IgG2b and IgG2c antibodies. In summary our findings suggest that helminth infection interfered with the control of retroviral infection by dampening the virus-specific neutralising antibody response.

The coincidental infection of a host with two different pathogens is widespread in low-income countries. Regions where helminth infections are endemic strongly overlap with areas where the incidence of viral infections such as HIV is high. HIV is a major public health issue causing more than 1 million deaths per year. To analyse the impact of a pre-existing helminth infection on a viral infection we established a helminth/retrovirus co-infection mouse model. Mice that were first infected with Litomosoides sigmodontis and subsequently with a murine retrovirus showed a more severe course of virus infection, i.e. exaggerated splenomegaly and higher viral loads. Since different lymphocytes such as B and T cells contribute to viral control we analysed the cellular and humoral immune response. While T cell responses were similar in co-infected and virus-infected mice, we observed reduced titres of virus-specific antibodies in co-infected mice. Our results suggest that helminth infection interfered with viral control by dampening the virus-specific antibody response. The viral infection itself altered the humoral immune response against L. sigmodontis without changing the worm burden. In summary, our data highlight the importance of deworming programs or vaccines against helminths in developing countries where the incidence of helminth/HIV co-infections is high.

Association between Taenia solium infection and HIV/AIDS in northern Tanzania: a matched cross sectional-study

BACKGROUND

The frequency of Taenia solium, a zoonotic helminth, is increasing in many countries of sub-Saharan Africa, where the prevalence of the human immunodeficiency virus (HIV) is also high. However, little is known about how these two infections interact. The aim of this study was to compare the proportion of HIV positive (+) and negative (-) individuals who are infected with Taenia solium (TSOL) and who present with clinical and neurological manifestations of cysticercosis (CC).

METHODS

In northern Tanzania, 170 HIV+ individuals and 170 HIV- controls matched for gender, age and village of origin were recruited. HIV staging and serological tests for TSOL antibodies (Ab) and antigen (Ag) were performed. Neurocysticercosis (NCC) was determined by computed tomography (CT) using standard diagnostic criteria. Neurological manifestations were confirmed by a standard neurological examination. In addition, demographic, clinical and neuroimaging data were collected. Further, CD4⁺ cell counts as well as information on highly active antiretroviral treatment (HAART) were noted.

RESULTS

No significant differences between HIV+ and HIV- individuals regarding the sero-prevalence of taeniosis-Ab (0.6% vs 1.2%), CC-Ab (2.4% vs 2.4%) and CC-Ag (0.6% vs 0.0%) were detected. A total of six NCC cases (3 HIV+ and 3 HIV-) were detected in the group of matched participants. Two individuals (1 HIV+ and 1 HIV-) presented with headaches as the main symptom for NCC, and four with asymptomatic NCC. Among the HIV+ group, TSOL was not associated with CD4⁺ cell counts, HAART duration or HIV stage.

CONCLUSIONS

This study found lower prevalence of taeniosis, CC and NCC than had been reported in the region to date. This low level of infection may have resulted in an inability to find cross-sectional associations between HIV status and TSOL infection or NCC. Larger sample sizes will be required in future studies conducted in that area to conclude if HIV influences the way NCC manifests itself.

Antihelminthics in helminth-endemic areas: effects on HIV disease progression

BACKGROUND

Helminth infections, such as soil-transmitted helminths, schistosomiasis, onchocerciasis, and lymphatic filariasis, are prevalent in many countries where human immunodeficiency virus (HIV) infection is also common. There is some evidence from observational studies that HIV and helminth co-infection may be associated with higher viral load and lower CD4+ cell counts. Treatment of helminth infections with antihelminthics (deworming drugs) may have benefits for people living with HIV beyond simply clearance of worm infections.This is an update of a Cochrane Review published in 2009 and we have expanded it to include outcomes of anaemia and adverse events.

OBJECTIVES

To evaluate the effects of deworming drugs (antihelminthic therapy) on markers of HIV disease progression, anaemia, and adverse events in children and adults.

SEARCH METHODS

In this review update, we searched online for published and unpublished studies in the Cochrane Library, MEDLINE, EMBASE, CENTRAL, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICRTP), ClinicalTrials.gov, and the WHO Global Health Library up to 29 September 2015. We also searched databases listing conference abstracts, scanned reference lists of articles, and contacted the authors of included studies.

SELECTION CRITERIA

We searched for randomized controlled trials (RCTs) that compared antihelminthic drugs with placebo or no intervention in HIV-positive people.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trials for eligibility and risk of bias. The primary outcomes were changes in HIV viral load and CD4+ cell count, and secondary outcomes were anaemia, iron deficiency, adverse events, and mortality events. We compared the effects of deworming using mean differences, risk ratios (RR), and 95% confidence intervals (CIs). We assessed the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Eight trials met the inclusion criteria of this review, enrolling a total of 1612 participants. Three trials evaluated the effect of providing antihelminthics to all adults with HIV without knowledge of their helminth infection status, and five trials evaluated the effects of providing deworming drugs to HIV-positive individuals with confirmed helminth infections. Seven trials were conducted in sub-Saharan Africa and one in Thailand. Antihelminthics for people with unknown helminth infection statusProviding antihelminthics (albendazole and praziquantel together or separately) to HIV-positive adults with unknown helminth infection status may have a small suppressive effect on mean viral load at six weeks but the 95% CI includes the possibility of no effect (difference in mean change -0.14 log10 viral RNA/mL, 95% CI -0.35 to 0.07, P = 0.19; one trial, 166 participants, low quality evidence).Repeated dosing with deworming drugs over two years (albendazole every three months plus annual praziquantel), probably has little or no effect on mean viral load (difference in mean change 0.01 log10 viral RNA, 95% CI: -0.03 to -0.05; one trial, 917 participants, moderate quality evidence), and little or no effect on mean CD4+ count (difference in mean change 2.60 CD4+ cells/µL, 95% CI -10.15 to 15.35; P = 0.7; one trial, 917 participants, low quality evidence). Antihelminthics for people with confirmed helminth infectionsTreating confirmed helminth infections in HIV-positive adults may have a small suppressive effect on mean viral load at six to 12 weeks following deworming (difference in mean change -0.13 log10 viral RNA, 95% CI -0.26 to -0.00; P = 0.04; four trials, 445 participants, low quality evidence). However, this finding is strongly influenced by a single study of praziquantel treatment for schistosomiasis. There may also be a small favourable effect on mean CD4+ cell count at 12 weeks after deworming in HIV-positive populations with confirmed helminth infections (difference in mean change 37.86 CD4+ cells/µL, 95% CI 7.36 to 68.35; P = 0.01; three trials, 358 participants, low quality evidence). Adverse events and mortality There is no indication that antihelminthic drugs impart additional risks in HIV-positive populations. However, adverse events were not well reported (very low quality evidence) and trials were underpowered to evaluate effects on mortality (low quality evidence).

AUTHORS' CONCLUSIONS

There is low quality evidence that treating confirmed helminth infections in HIV-positive adults may have small, short-term favourable effects on markers of HIV disease progression. Further studies are required to confirm this finding. Current evidence suggests that deworming with antihelminthics is not harmful, and this is reassuring for the routine treatment of confirmed or suspected helminth infections in people living with HIV in co-endemic areas.Further long-term studies are required to make confident conclusions regarding the impact of presumptively deworming all HIV-positive individuals irrespective of helminth infection status, as the only long-term trial to date did not demonstrate an effect.

Potentially zoonotic helminthiases of murid rodents from the Indo-Chinese peninsula: impact of habitat and the risk of human infection

In this study, we report the potential rodent-borne zoonotic helminths in wild-caught murid rodents from four categorized habitats-forest, nonflooded land, irrigated land, and human settlement in seven localities of Thailand, Cambodia, and Lao PDR. Out of 2478 rodent samples, 735 (29.7%) were infected by at least one of the following zoonotic helminth species: Echinostoma malayanum, Echinostoma ilocanum, Plagiorchis muris, Raillietina spp., Hymenolepis diminuta, Hymenolepis nana, Cyclodontostomum purivisi, and Moniliformis moniliformis. Raillietina spp. showed the highest prevalence (13.8%), followed by H. diminuta (8.6%), H. nana (6.7%), and C. purvisi (1.0%). Habitat affected the intensity of helminth infection in murid rodent hosts. Specific habitats favoring each zoonotic helminth species are discussed in relation to the risk of human infection. Season and host maturity influenced intensity of total zoonotic helminths, but there was no influence of host gender. However, in terms of individual helminth species, female rodents were more infected by E. malayanum, E. ilocanum, and C. purvisi than males. Among the rodent species, Rattus tanezumi seems to play the most important role as a reservoir by hosting seven zoonotic heminth species. This rat is ubiquitously found in all types of the habitats, suggesting that it can act as an important bridge species, carrying parasites across different habitats.

Deworming and the immune status of HIV positive pre-antiretroviral therapy individuals in Arba Minch, Chencha and Gidole hospitals, Southern Ethiopia

Background

Helminths/HIV co-infections are very common in developing countries, especially in Africa. The effect of overlapping distribution of HIV and helminths becomes important because concomitant infection may exacerbate disease outcome of HIV infection. The study aimed at determining the effect of deworming on the immune status of helminth/HIV coinfected Pre-ART HIV patients attending three health institutions in Southern Ethiopia.

Methods

97 HIV-positive Pre-ART individuals were observed into 2 groups on the basis of helminth co-infection and no infection. Out of these, 66 study participants were helminths/HIV co-infected and the remaining 31 study participants were helminths (−)/HIV (+) control. Helminth/HIV co-infected participants CD4+ T-cell count was done at baseline, after 15 weeks and 6 months after antihelminthics treatment. Data were analyzed using SPSS version 16.

Results

Ascaris lumbricoides was the highest prevalent soil transmitted helminths in Pre-ART individuals in this study. CD4+ T-cell count in the Ascaris lumricoides/HIV co-infected was significantly higher (P = 0.05) and (P < 0.05) after 15 weeks and 6 months post-antihelminthics treatment respectively. Also, after antihelminthic therapy, the CD4+ T-cell count significantly increased (P < 0.005) in all treated helminth infections.

Conclusions

The study showed that treatment of ascariasis had a significant effect on CD4+ T-cell count increase in the treated Pre-ART Ascaris lumbricoides/HIV co-infected individuals; whereas the same positive effect was not evident for other intestinal helminth parasites detected in the study. In conclusion, this finding on Ascaris lumbricoides-specific nature of immune interaction in helminth/HIV co-infection may partly explain the inconsistent reports on the role of intestinal helminths on progression of HIV infection to AIDS. Therefore, a well-designed longitudinal study on helminth species-specific HIV/helminth co-infection will be needed to fully establish the possible benefits of deworming in intestinal helminth/HIV co-infection.

Effect of deworming on Th2 immune response during HIV-helminths co-infection

Background

Helminths infections have been suggested to worsen the outcome of HIV infection by polarizing the immune response towards Th2. The purpose of this study is to determine the activity of Th2 immune response by measuring total serum IgE level during symptomatic and asymptomatic HIV infection with and without helminths co-infection and to define the role of deworming and/or ART on kinetics of serum IgE.

Methods

This prospective comparative study was conducted among symptomatic HIV-1 infected adults, treatment naïve asymptomatic HIV positive individuals and HIV negative apparently healthy controls with and without helminths co-infection. Detection and quantification of helminths and determination of serum IgE level, CD4⁺, and CD8⁺ T cell count were done at baseline and 12 weeks after ART and/or deworming.

Results

HIV patients co-infected with helminths showed a high level of serum IgE compared to HIV patients without helminths co-infection (1,688 [IQR 721–2,473] versus 1,221 [IQR 618–2,289] IU/ml; P = 0.022). This difference was also markedly observed between symptomatic HIV infected patients after with and without helminths infection (1,690 [IQR 1,116–2,491] versus 1,252 [703–2,251] IU/ml; P = 0.047). A significant decline in serum IgE level was observed 12 weeks after deworming and ART of symptomatic HIV infected patients with (1,487 versus 992, P = 0.002) and without (1,233 versus 976 IU/ml, P = 0.093) helminths co-infection. However, there was no significant decrease in serum IgE level among asymptomatic HIV infected individuals (1,183 versus 1,097 IU/ml, P = 0.13) and apparently health controls (666 IU/ml versus 571, P = 0.09) without helminths co-infection 12 weeks after deworming.

Conclusions

The significant decline of serum IgE level 12 weeks after deworming of both symptomatic and asymptomatic patients indicate a tendency to down-regulate the Th2 immune response and is additional supportive evidence that deworming positively impacts HIV/AIDS diseases progression. Thus, deworming should be integrated with ART program in helminths endemic areas of tropical countries.

Treatment of W. bancrofti (Wb) in HIV/Wb coinfections in South India

Background

The disease course of human immunodeficiency virus (HIV) is often altered by existing or newly acquired coincident infections.

Methodology/Principal Findings

To assess the influence of pre-existing Wuchereria bancrofti infection on HIV progression, we performed a case-controlled treatment study of HIV positive individuals with (FIL+) or without (FIL-) W. bancrofti infection. Twenty-eight HIV+/FIL+ and 51 matched HIV+/FIL- subjects were treated with a single dose of diethylcarbamazine and albendazole (DEC/Alb) and followed for a year at regular intervals. Sixteen of the HIV+/FIL+ subjects (54%) and 28 of the HIV+/FIL- controls (57%) were on antiretroviral therapy (ART) during the study. Following treatment, no differences were noted in clinical outcomes between the 2 groups. There also was no significant difference between the groups in the HIV viral load at 12 months as a percentage of baseline viral load (HIV+/FIL+ group had on average 0.97 times the response of the HIV+/FIL- group, 95% CI 0.88, 1.07) between the groups. Furthermore, there were no significant differences found in either the change in viral load at 1, 3, or 6 months or in the change in CD4 count at 3, 6, or 12 months between the 2 groups.

Conclusions/Significance

We were unable to find a significant effect of W. bancrofti infection or its treatment on HIV clinical course or surrogate markers of HIV disease progression though we recognized that our study was limited by the smaller than predicted sample size and by the use of ART in half of the patients. Treatment of W. bancrofti coinfection in HIV positive subjects (as is usual in mass drug administration campaigns) did not represent an increased risk to the subjects, and should therefore be considered for PLWHA living in W. bancrofti endemic areas.

Trial Registration

ClinicalTrials.gov NCT00344279

In people living with HIV infection, simultaneous infections can adversely affect HIV disease. This has been seen with bacterial (tuberculosis), viral (cytomegalovirus), and parasitic infections (toxoplasmosis). Lymphatic filariasis is caused by a thin thread-like parasite that lives in the lymph vessels of infected people. It can cause significant disability. This infection is found in much of the same areas that high levels of HIV infection. We were interested in knowing if lymphatic filariasis changed the course of HIV infection in people with both diseases. In this study, the authors enrolled people in India who were living with HIV who either had or didn’t have filarial infection. All patients were treated for filariasis with 2 drugs, and then were followed for 1 year to see how their HIV disease progressed. No difference in HIV disease progression was found between the groups that did or did not have filariasis before treatment. The patients with HIV did well with the medicine for filariasis.

Schistosoma haematobium infection and CD4+ T-cell levels: a cross-sectional study of young South African women

Schistosoma (S.) haematobium causes urogenital schistosomiasis and has been hypothesized to adversely impact HIV transmission and progression. On the other hand it has been hypothesized that HIV could influence the manifestations of schistosomiasis. In this cross-sectional study, we explored the association between urogenital S. haematobium infection and CD4 cell counts in 792 female high-school students from randomly selected schools in rural KwaZulu-Natal, South Africa. We also investigated the association between low CD4 cell counts in HIV positive women and the number of excreted schistosome eggs in urine. Sixteen percent were HIV positive and 31% had signs of urogenital schistosomiasis (as determined by genital sandy patches and / or abnormal blood vessels on ectocervix / vagina by colposcopy or presence of eggs in urine). After stratifying for HIV status, participants with and without urogenital schistosomiasis had similar CD4 cell counts. Furthermore, there was no significant difference in prevalence of urogenital schistosomiasis in HIV positive women with low and high CD4 cell counts. There was no significant difference in the number of eggs excreted in urine when comparing HIV positive and HIV negative women. Our findings indicate that urogenital schistosomiasis do not influence the number of circulating CD4 cells.

Worms and Humans: A Happy Divorce?

Chronic asymptomatic worm infection, often in combination with tuberculosis (TB), is common in low-income countries. Indeed, a life without worm infestation, as is now the case in most high-income countries, is a recent condition for humankind. Worms and Mycobacterium tuberculosis give rise to different immune response patterns (Th2 vs. Th1 driven), and we have studied whether chronic worm infection affects the susceptibility to and control of TB in the low income country of Ethiopia. Our results, as well of those in the general literature, are inconclusive, although we have some rather strong data in support of adult deworming in relation to vaccination with bacillus Calmette-Guérin (BCG) against TB. In addition, we discuss briefly the putative relationship between chronic worm infestation and autoimmunity/allergy.

Empiric deworming and CD4 count recovery in HIV-infected Ugandans initiating antiretroviral therapy

BACKGROUND

There is conflicting evidence on the immunologic benefit of treating helminth co-infections ("deworming") in HIV-infected individuals. Several studies have documented reduced viral load and increased CD4 count in antiretroviral therapy (ART) naïve individuals after deworming. However, there are a lack of data on the effect of deworming therapy on CD4 count recovery among HIV-infected persons taking ART.

METHODOLOGY/PRINCIPAL FINDINGS

To estimate the association between empiric deworming therapy and CD4 count after ART initiation, we performed a retrospective observational study among HIV-infected adults on ART at a publicly operated HIV clinic in southwestern Uganda. Subjects were assigned as having received deworming if prescribed an anti-helminthic agent between 7 and 90 days before a CD4 test. To estimate the association between deworming and CD4 count, we fit multivariable regression models and analyzed predictors of CD4 count, using a time-by-interaction term with receipt or non-receipt of deworming. From 1998 to 2009, 5,379 subjects on ART attended 21,933 clinic visits at which a CD4 count was measured. Subjects received deworming prior to 668 (3%) visits. Overall, deworming was not associated with a significant difference in CD4 count in either the first year on ART (β = 42.8; 95% CI, -2.1 to 87.7) or after the first year of ART (β =  -9.9; 95% CI, -24.1 to 4.4). However, in a sub-analysis by gender, during the first year of ART deworming was associated with a significantly greater rise in CD4 count (β = 63.0; 95% CI, 6.0 to 120.1) in females.

CONCLUSIONS/SIGNIFICANCE

Empiric deworming of HIV-infected individuals on ART conferred no significant generalized benefit on subsequent CD4 count recovery. A significant association was observed exclusively in females and during the initial year on ART. Our findings are consistent with recent studies that failed to demonstrate an immunologic advantage to empirically deworming ART-naïve individuals, but suggest that certain sub-populations may benefit.

Triple NF-kB binding sites and LTR sequence similarities in HIV-1C isolates irrespective of helminth co-infection

BACKGROUND

Helminth infections as well as structural alternations in the long-terminal repeat (LTR) regions of HIV-1 are known to contribute to elevated HIV RNA level and enhance HIV-1 diseases progression. However, the impact of helminths infections on the occurrences of triple NF-κB and genetic variability in LTR region of HIV-1C isolates is not known. We aimed to examine the presence of genetic variability in the LTR region of HIV-1C isolates during chronic HIV-helminth co-infection.

METHODS

HIV-1C infected Ethiopians with (n = 22) and without (n = 20) helminth infection were included. The LTR region of HIV was amplified and sequenced. Sequences were aligned with reference set from the Los Alamos HIV database. Phylogenetic analysis and frequency of polymorphic changes was performed by the neighbour-joining method using Geneious Basic software.

RESULTS

All LTR sequences from patients with or without of helminth co-infection clustered with HIV-1 subtype C with two distinct subclusters (C and C'). The enhancer element was found to have three copies of 10-base pair binding sites for NF-κBs which is an evidence for predominance of triple NF-κB sites (94%) in HIV-1C isolates irrespective of helminths co-infection and subclusters. Moreover, irrespective of helminth co-infection and C/C' subclusters high sequences similarity in LTR was observed. There was no significant difference in plasma HIV RNA level between HIV-1 C and C' subclusters.

CONCLUSIONS

Despite the small sample size, the predominance of triple NF-κB binding sites and high sequence similarities in LTR region irrespective of helminths infection suggest the natural occurrence of the three NF-κB binding sites in HIV-1C isolates without the influence of secondary infection. Thus, the higher HIV-1C viraemia in helminth co-infected individuals is more likely a result of immune activation rather than LTR sequence variation. Moreover, the lack of significant difference in plasma HIV RNA level between HIV-1 C and C' subcluster may show the lack of functional differences among the two groups.

Risk factors for intestinal parasitosis among antiretroviral-treated HIV/AIDS patients in Ethiopia

Summary A cross-sectional survey was conducted to determine the risk factors associated with intestinal parasitosis in HIV/AIDS patients receiving antiretroviral therapy (ART). Socio-demographic information was collected and faecal samples were analysed from 384 randomly selected patients on ART. Data on CD4+ T-cell counts and World Health Organization clinical staging were obtained from the medical records at the hospital. The overall prevalence of intestinal parasitosis was 56% (95% confidence interval [CI]: 51% to 61%). No opportunistic intestinal parasites or Schistosoma haematobium eggs were detected. Unavailability of latrine and lack of hand washing with soap were associated with Entamoeba histolytica/dispar (adjusted odds ratio [AOR], 2.75; 95% CI: 1.77 to 4.27 and AOR, 2.67; 95% CI: 1.60 to 4.44, respectively) and Giardia lamblia (AOR, 2.08; 95% CI: 1.08 to 3.99 and AOR, 2.46; 95% CI: 1.06 to 5.75, respectively) infections. Intestinal parasitosis was significantly associated with low CD4 cell count (p = 0.002). In contrast, intestinal parasitic infections were not associated (p > 0.05) with the World Health Organization disease staging. In summary, poor personal hygiene and sanitation practice contributed to the high prevalence of intestinal parasitosis. Routine diagnosis for intestinal parasitic infections should be performed in patients attending ART clinics in this setting.

Effect of helminth-induced immunity on infections with microbial pathogens

Helminth infections are ubiquitous worldwide and can trigger potent immune responses that differ from and potentially antagonize host protective responses to microbial pathogens. In this Review we focus on the three main killers in infectious disease-AIDS, tuberculosis and malaria-and critically assesses whether helminths adversely influence host control of these diseases. We also discuss emerging concepts for how M2 macrophages and helminth-modulated dendritic cells can potentially influence the protective immune response to concurrent infections. Finally, we present evidence advocating for more efforts to determine how and to what extent helminths interfere with the successful control of specific concurrent coinfections.

Shortening the 'short-course' therapy- insights into host immunity may contribute to new treatment strategies for tuberculosis

Achieving global control of tuberculosis (TB) is a great challenge considering the current increase in multidrug resistance and mortality rate. Considerable efforts are therefore being made to develop new effective vaccines, more effective and rapid diagnostic tools as well as new drugs. Shortening the duration of TB treatment with revised regimens and modes of delivery of existing drugs, as well as development of new antimicrobial agents and optimization of the host response with adjuvant immunotherapy could have a profound impact on TB cure rates. Recent data show that chronic worm infection and deficiencies in micronutrients such as vitamin D and arginine are potential areas of intervention to optimize host immunity. Nutritional supplementation to enhance nitric oxide production and vitamin D-mediated effector functions as well as the treatment of worm infection to reduce immunosuppressive effects of regulatory T (Treg) lymphocytes may be more suitable and accessible strategies for highly endemic areas than adjuvant cytokine therapy. In this review, we focus mainly on immune control of human TB, and discuss how current treatment strategies, including immunotherapy and nutritional supplementation, could be optimized to enhance the host response leading to more effective treatment.

Chronic bystander infections and immunity to unrelated antigens

Chronic infections with persistent pathogens such as helminths, mycobacteria, Plasmodium, and hepatitis viruses affect more than a third of the human population and are associated with increased susceptibility to other pathogens as well as reduced vaccine efficacy. Although these observations suggest an impact of chronic infections in modulating immunity to unrelated antigens, little is known regarding the underlying mechanisms. Here, we summarize evidence of the most prevalent infections affecting immunity to unrelated pathogens and vaccines, and discuss potential mechanisms of how different bystander chronic infections might impact immune responses. We suggest that bystander chronic infections affect different stages of host responses and may impact transmission and recognition of other pathogens, innate immune responses, priming and differentiation of adaptive effector responses, as well as the development and maintenance of immunological memory. Further understanding of the immunological effects of coinfection should provide opportunities to enhance vaccine efficacy and control of infectious diseases.

Chronic schistosome infection leads to modulation of granuloma formation and systemic immune suppression

Schistosome worms have been infecting humans for millennia, but it is only in the last half century that we have begun to understand the complexities of this inter-relationship. As our sophistication about the inner workings of every aspect of the immune system has increased, it has also become obvious that schistosome infections have broad ranging effects on nearly all of the innate and adaptive immune response mechanisms. Selective pressures on both the worms and their hosts, has no doubt led to co-evolution of protective mechanisms, particularly those that favor granuloma formation around schistosome eggs and immune suppression during chronic infection. The immune modulatory effects that chronic schistosome infection and egg deposition elicit have been intensely studied, not only because of their major implications to public health issues, but also due to the emerging evidence that schistosome infection may protect humans from severe allergies and autoimmunity. Mouse models of schistosome infection have been extremely valuable for studying immune modulation and regulation, and in the discovery of novel aspects of immunity. A progression of immune reactions occurs during granuloma formation ranging from innate inflammation, to activation of each branch of adaptive immune response, and culminating in systemic immune suppression and granuloma fibrosis. Although molecular factors from schistosome eggs have been identified as mediators of immune modulation and suppressive functions of T and B cells, much work is still needed to define the mechanisms of the immune alteration and determine whether therapies for asthma or autoimmunity could be developed from these pathways.

Epidemiology and interactions of Human Immunodeficiency Virus - 1 and Schistosoma mansoni in sub-Saharan Africa

Human Immunodeficiency Virus-1/AIDS and Schistosoma mansoni are widespread in sub-Saharan Africa and co-infection occurs commonly. Since the early 1990s, it has been suggested that the two infections may interact and potentiate the effects of each other within co-infected human hosts. Indeed, S. mansoni infection has been suggested to be a risk factor for HIV transmission and progression in Africa. If so, it would follow that mass deworming could have beneficial effects on HIV-1 transmission dynamics. The epidemiology of HIV in African countries is changing, shifting from urban to rural areas where the prevalence of Schistosoma mansoni is high and public health services are deficient. On the other side, the consequent pathogenesis of HIV-1/S. mansoni co-infection remains unknown. Here we give an account of the epidemiology of HIV-1 and S. mansoni, discuss co-infection and possible biological causal relationships between the two infections, and the potential impact of praziquantel treatment on HIV-1 viral loads, CD4+ counts and CD4+/CD8+ ratio. Our review of the available literature indicates that there is evidence to support the hypothesis that S. mansoni infections can influence the replication of the HIV-1, cell-to-cell transmission, as well as increase HIV progression as measured by reduced CD4+ T lymphocytes counts. If so, then deworming of HIV positive individuals living in endemic areas may impact on HIV-1 viral loads and CD4+ T lymphocyte counts.

Empiric deworming to delay HIV disease progression in adults with HIV who are ineligible for initiation of antiretroviral treatment (the HEAT study): a multi-site, randomised trial

BACKGROUND

Co-infection with HIV and helminths is common in sub-Saharan Africa and findings from previous studies have suggested that anthelmintic treatment might delay immunosuppression in people with HIV. We aimed to assess the efficacy of empiric deworming of adults with HIV in delaying HIV disease progression.

METHODS

In this non-blinded randomised trial, we enrolled adults (aged ≥18 years) with HIV who did not meet criteria for the initiation of antiretroviral treatment from three sites in Kenya. Using a computer-generated sequence, we randomly assigned (1:1) eligible participants to either empiric albendazole every 3 months plus praziquantel annually (treatment group) or to standard care (control group). Participants were followed up for 24 months. We measured CD4 cell counts every 6 months and plasma HIV RNA annually. The primary endpoints were a CD4 count of less than 350 cells per μL and a composite endpoint consisting of the first occurrence of a CD4 count of less than 350 cells per μL, first reported use of antiretroviral treatment, and non-traumatic deaths. We compared these measures by use of Cox proportional hazards regression and Kaplan-Meier survival analyses. Primary analysis was done by intention to treat. The trial was registered with ClinicalTrials.gov, number NCT0050722.

FINDINGS

Between Feb 6, 2008, and June 21, 2011, we enrolled and followed-up 948 participants; 469 were allocated to the treatment group and 479 to the control group. All participants were provided with co-trimoxazole prophylaxis. Median baseline CD4 cell counts and HIV RNA concentrations did not differ between groups. We recorded no statistically significant difference between the treatment and control groups in the number of people reaching a CD4 count of fewer than 350 cells per μL (41·6 events per 100 person-years vs 46·2 events per 100 person-years; hazard ratio 0·89, 95% CI 0·75-1·06, p=0·2) or the composite endpoint (44·0 events per 100 person-years vs 49·8 events per 100 person-years; 0·88, 0·74-1·04, p=0·1). Serious adverse events, none of which thought to be treatment-related, occurred at a similar frequency in both groups.

INTERPRETATION

Our findings do not suggest an effect of empiric deworming in the delaying of HIV disease progression in adults with HIV in an area where helminth infection is common. Alternative approaches are needed to delay HIV disease progression in areas where co-infections are common.

Epidemiology and immunology of helminth-HIV interactions

PURPOSE OF REVIEW

Helminths and HIV-1 use multiple mechanisms to avoid or deviate immune responses, and these mechanisms may interact with important consequences for the epidemiology of each infection. In this review, we summarize recent immunological and epidemiological advances in the understanding of HIV-1-helminth co-infections.

RECENT FINDINGS

Considering the extent of geographical overlap of these chronic infections, there has been so far surprisingly limited and inconsistent evidence of important interactive effects, either from epidemiological studies examining associations between helminth infection indicators and HIV disease parameters, or from studies that have dissected the immune mechanisms triggered by each pathogen in isolation and investigated their interaction. Systematic reviews have found inconsistent evidence for a beneficial effect of anthelmintic treatment of helminth-HIV-1 co-infected individuals on viral load or CD4 cell counts. It is not certain that co-infection with HIV-1 and helminths will always be more detrimental to the host than either single infection alone, or that intervening against co-infections will have only beneficial effects.

SUMMARY

A consensus on the implications of co-infection on de-worming and vaccination policies has not yet emerged. Well powered randomized trials in HIV-1-infected individuals with defined helminth infections are required to determine the benefits of anthelmintic interventions.

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.

Species-specific treatment effects of helminth/HIV-1 co-infection: a systematic review and meta-analysis

In sub-Saharan Africa, over 22 million people are estimated to be co-infected with both helminths and HIV-1. Several studies have suggested that de-worming individuals with HIV-1 may delay HIV-1 disease progression, and that the benefit of de-worming may vary by individual helminth species. We conducted a systematic review and meta-analysis of the published literature to determine the effect of treatment of individual helminth infections on markers of HIV-1 progression (CD4 count and HIV viral load). There was a trend towards an association between treatment for Schistosoma mansoni and a decrease in HIV viral load (Weighted mean difference (WMD)=-0·10; 95% Confidence interval (CI): -0·24, 0·03), although this association was not seen for Ascaris lumbricoides, hookworm or Trichuris trichiura. Treatment of A. lumbricoides, S. mansoni, hookworm or T. trichiura was not associated with a change in CD4 count. While pooled data from randomized trials suggested clinical benefit of de-worming for individual helminth species, these effects decreased when observational data were included in the pooled analysis. While further trials are needed to confirm the role of anthelmintic treatment in HIV-1 co-infected individuals, providing anthelmintics to individuals with HIV-1 may be a safe, inexpensive and practical intervention to slow progression of HIV-1.

High prevalence of persistent parasitic infections in foreign-born, HIV-infected persons in the United States

BACKGROUND

Foreign-born, HIV-infected persons are at risk for sub-clinical parasitic infections acquired in their countries of origin. The long-term consequences of co-infections can be severe, yet few data exist on parasitic infection prevalence in this population.

METHODOLOGY/PRINCIPAL FINDINGS

This cross-sectional study evaluated 128 foreign-born persons at one HIV clinic. We performed stool studies and serologic testing for strongyloidiasis, schistosomiasis, filarial infection, and Chagas disease based on the patient's country of birth. Eosinophilia and symptoms were examined as predictors of helminthic infection. Of the 128 participants, 86 (67%) were male, and the median age was 40 years; 70 were Mexican/Latin American, 40 African, and 18 from other countries or regions. Strongyloides stercoralis antibodies were detected in 33/128 (26%) individuals. Of the 52 persons from schistosomiasis-endemic countries, 15 (29%) had antibodies to schistosome antigens; 7 (47%) had antibodies to S. haematobium, 5 (33%) to S. mansoni, and 3 (20%) to both species. Stool ova and parasite studies detected helminths in 5/85 (6%) persons. None of the patients tested had evidence of Chagas disease (n = 77) or filarial infection (n = 52). Eosinophilia >400 cells/mm(3) was associated with a positive schistosome antibody test (OR 4.5, 95% CI 1.1-19.0). The only symptom significantly associated with strongyloidiasis was weight loss (OR 3.1, 95% CI 1.4-7.2).

CONCLUSIONS/SIGNIFICANCE

Given the high prevalence of certain helminths and the potential lack of suggestive symptoms and signs, selected screening for strongyloidiasis and schistosomiasis or use of empiric antiparasitic therapy may be appropriate among foreign-born, HIV-infected patients. Identifying and treating helminth infections could prevent long-term complications.

Effect of treating co-infections on HIV-1 viral load: a systematic review

Co-infections contribute to HIV-related pathogenesis and often increase viral load in HIV-infected people. We did a systematic review to assess the effect of treating key co-infections on plasma HIV-1-RNA concentrations in low-income countries. We identified 18 eligible studies for review: two on tuberculosis, two on malaria, six on helminths, and eight on sexually transmitted infections, excluding untreatable or non-pathogenic infections. Standardised mean plasma viral load decreased after the treatment of co-infecting pathogens in all 18 studies. The standardised mean HIV viral-load difference ranged from -0.04 log(10) copies per mL (95% CI -0.24 to 0.16) after syphilis treatment to -3.47 log(10) copies per mL (95% CI -3.78 to -3.16) after tuberculosis treatment. Of 14 studies with variance data available, 12 reported significant HIV viral-load differences before and after treatment. Although many of the viral-load reductions were 1.0 log(10) copies per mL or less, even small changes in plasma HIV-RNA concentrations have been shown to slow HIV progression and could translate into population-level benefits in lowering HIV transmission risk.

Prevalence and correlates of helminth co-infection in Kenyan HIV-1 infected adults

Background

Deworming HIV-1 infected individuals may delay HIV-1 disease progression. It is important to determine the prevalence and correlates of HIV-1/helminth co-infection in helminth-endemic areas.

Methods

HIV-1 infected individuals (CD4>250 cells/ul) were screened for helminth infection at ten sites in Kenya. Prevalence and correlates of helminth infection were determined. A subset of individuals with soil-transmitted helminth infection was re-evaluated 12 weeks following albendazole therapy.

Results

Of 1,541 HIV-1 seropositive individuals screened, 298 (19.3%) had detectable helminth infections. Among individuals with helminth infection, hookworm species were the most prevalent (56.3%), followed by Ascaris lumbricoides (17.1%), Trichuris trichiura (8.7%), Schistosoma mansoni (7.1%), and Stongyloides stercoralis (1.3%). Infection with multiple species occurred in 9.4% of infections. After CD4 count was controlled for, rural residence (RR 1.40, 95% CI: 1.08–1.81), having no education (RR 1.57, 95% CI: 1.07–2.30), and higher CD4 count (RR 1.36, 95% CI: 1.07–1.73) remained independently associated with risk of helminth infection. Twelve weeks following treatment with albendazole, 32% of helminth-infected individuals had detectable helminths on examination. Residence, education, and CD4 count were not associated with persistent helminth infection.

Conclusions

Among HIV-1 seropositive adults with CD4 counts above 250 cells/mm³ in Kenya, traditional risk factors for helminth infection, including rural residence and lack of education, were associated with co-infection, while lower CD4 counts were not.

Trial Registration

ClinicalTrials.gov NCT00130910

Over one-third of people worldwide are currently infected with parasitic worms. The majority of these infections occur in sub-Saharan Africa, where over half of the population may be infected with at least one type of parasitic worm. HIV infection is also common in many of these countries, and there is significant geographic overlap in the presence of HIV and worm infection. Several studies have suggested that treatment of worm infections in people with HIV may delay the progression of HIV disease. Treatment has been shown to both decrease levels of the HIV virus in the blood of people with HIV and to increase the number of immune cells (CD4 cells) targeted by HIV. It is important to determine which populations of HIV-infected individuals are at greatest risk of worm infection in order to develop potential interventions for the treatment and prevention of worm infection in HIV-infected individuals. We report findings from a large study examining the prevalence and associated co-factors for worm infection among individuals at ten sites in Kenya.

Complexity, cofactors, and the failure of AIDS policy in Africa

Global AIDS policy still treats HIV as an exceptional case, abstracting from the context in which infection occurs. Policy is based on a simplistic theory of HIV causation, and evaluated using outdated tools of health economics. Recent calls for a health systems strategy – preventing and treating HIV within a programme of comprehensive health care – have not yet influenced the silo approach of AIDS policy.

Evidence continues to accumulate, showing that multiple factors, such as malnutrition, malaria and helminthes, increase the risk of sexual and vertical transmission of HIV. Moreover, complementary interventions that reduce viral load, improve immune response, and interrupt pathways of transmission could increase the effectiveness of antiretroviral drugs and other tools of AIDS policy.

In health economics, the omission of estimates of increasing returns generated by disease or treatment synergies biases cost-effectiveness analysis against multiple, yet inexpensive, interventions. Current tools of cost-effectiveness analysis only identify local maxima in a complex landscape, and can play, at best, a marginal role in the epidemic, especially where it is already generalized.

Cost-effectiveness analyses for HIV that are based on the wrong epidemiological model can generate Type III errors: we get precise answers to the wrong questions about how to intervene. To control the epidemic, AIDS policy needs to utilize an epidemiological model that reflects the interactions of biological as well as behavioural variables that determine the course of HIV epidemics around the world. Cost-effectiveness analysis can benefit from using economic concepts of externalities and increasing returns to incorporate disease interactions and beneficial treatment spillovers for coinfections in HIV-prevention policy.

Deworming helminth co-infected individuals for delaying HIV disease progression

BACKGROUND

The HIV-1 pandemic has disproportionately affected individuals in resource-constrained settings where other infectious diseases, such as helminth infections, also are highly prevalent. There are biologically plausible reasons for possible effects of helminth infection in HIV-1-infected individuals, and findings from multiple studies suggest that helminth infection may adversely affect HIV-1 progression. Since initial publication of this review (Walson 2007), additional data from randomized controlled trials (RCTs) has become available. We sought to evaluate all currently available evidence to determine if treatment of helminth infection in HIV-1 co-infected individuals impacts HIV-1 progression.

OBJECTIVES

To determine if treating helminth infection in individuals with HIV-1 can reduce the progression of HIV-1 as determined by changes in CD4 count, viral load, or clinical disease progression.

SEARCH STRATEGY

In this 2008 update, we searched online for published and unpublished studies in The Cochrane Library, MEDLINE, EMBASE, CENTRAL, and AIDSEARCH. We also searched databases listing conference abstracts, scanned reference lists of articles, and contacted authors of included studies.

SELECTION CRITERIA

We searched for RCTs and quasi-RCTs that compared HIV-1 progression as measured by changes in CD4 count, viral load, or clinical disease progression in HIV-1 infected individuals receiving anti-helminthic therapy.

DATA COLLECTION AND ANALYSIS

Data regarding changes in CD4 count, HIV-1 RNA levels, and/or clinical staging after treatment of helminth co-infection were extracted from identified studies.

MAIN RESULTS

Of 7,019 abstracts identified (6,384 from original searches plus 635 from updated searches), 17 abstracts were identified as meeting criteria for potential inclusion (15 from previous review plus an additional two RCTs). After restricting inclusion to RCTs, a total of three studies were eligible for inclusion in this updated review.All three trials showed individual beneficial effects of helminth eradication on markers of HIV-1 disease progression (HIV-1 RNA and/or CD4 counts). When data from these trials were pooled, the analysis demonstrated significant benefit of deworming on both plasma HIV-1 RNA and CD4 counts.

AUTHORS' CONCLUSIONS

To date, three RCTs have evaluated the effects of deworming on markers of HIV-1 disease progression in helminth and HIV-1 co-infected individuals. All trials demonstrate benefit in attenuating or reducing plasma viral load and/or increasing CD4 counts. When taken together, there is evidence of benefit for deworming HIV-1 co-infected adults. Given that these studies evaluated different helminth species and different interventions, further trials are warranted to evaluate species-specific effects and to document long-term clinical outcomes following deworming.

Cofactor infections and HIV epidemics in developing countries: implications for treatment

This article shows that the burden of certain tropical disease infections, after controlling for other factors, is positively correlated with HIV prevalence. Using cross-national data and multivariate linear regression analysis, we investigate the determinants of HIV prevalence in low- and middle-income countries. We begin with social and economic variables used in other cross-national studies and then incorporate data on parasitic and infectious diseases endemic in poor populations, which are found to be strongly and significantly correlated with--and are potent predictors of--HIV prevalence. The paper concludes by arguing that treating tropical diseases may be a cost-effective add-on to HIV-prevention and -treatment programs, thus slowing the spread of HIV in disease-burdened populations.

Efficacy of different chemotherapeutic schemes for hookworm-infected villagers in China

A comparative analysis has been made of the efficacy of different chemotherapeutic schemes against hookworm infections in China. Hookworm eggs were detected by the improved Kato's thick smear method. Benzimidazole was offered to residents in the tested villages, while NaHCO3 was used as placebo in control villages. Data were analysed by negative binomial distribution with statistic software R2.2.1. In the tested village as a result of the application of selective chemotherapy, hookworm infection rate decreased from 58.79% to 1.08%, while the average of eggs per gram (EPG) reduced from 526.29 to 56.91. The infection rates in the target chemotherapy village and in the mass chemotherapy village declined from 6.90% to 1.92% and 10.10% to 0.65% respectively. It was concluded that the consecutive selective chemotherapy could rapidly decrease the infection rate and EPG of hookworm and maintain the infection rate at low level. The curative effect of the target chemotherapy was similar to that of the mass chemotherapy in the low hookworm endemic area.

Impact of small reductions in plasma HIV RNA levels on the risk of heterosexual transmission and disease progression

OBJECTIVE

To estimate the impact of small changes in plasma levels of HIV-1 RNA on the risk of heterosexual transmission or disease progression to an AIDS-defining event or death.

DESIGN AND METHODS

We systematically reviewed the published literature for studies that evaluated small viral load changes among antiretroviral-therapy-naive, adult populations. We modeled relative risk estimates for viral transmission and disease progression according to 0.3, 0.5, and 1.0 log10 increments of HIV load.

RESULTS

We calculated that the likelihood of transmitting HIV by heterosexual contact increased, on average, by 20% and that the annual risk of progression to an AIDS-defining illness or related death increased by 25% with every 0.3 log10 increment in HIV RNA. A 0.5 log10 increment in HIV RNA was associated with 40% greater risk of heterosexual transmission and 44% increased risk of progression to AIDS or death. A 1.0 log10 increment in HIV RNA was associated with 100% greater risk of heterosexual transmission and 113% increased risk of progression to AIDS or death.

CONCLUSION

Antiretroviral therapy continues to be unavailable or not-yet-indicated for 72% of the world's HIV-infected persons. Mounting evidence that treatment of coinfections may reduce HIV viral load, even modestly, suggests the priority of improved adjunctive care for HIV-infected persons even without antiretroviral therapy, both to slow disease progression and to reduce infectiousness.

Albendazole treatment of HIV-1 and helminth co-infection: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

Several co-infections have been shown to impact the progression of HIV-1 infection. We sought to determine if treatment of helminth co-infection in HIV-1-infected adults impacted markers of HIV-1 disease progression.

DESIGN

To date, there have been no randomized trials to examine the effects of soil-transmitted helminth eradication on markers of HIV-1 progression.

METHODS

A randomized, double-blind, placebo-controlled trial of albendazole (400 mg daily for 3 days) in antiretroviral-naive HIV-1-infected adults (CD4 cell count >200 cells/microl) with soil-transmitted helminth infection was conducted at 10 sites in Kenya (ClinicalTrials.gov NCT00130910). CD4 and plasma HIV-1 RNA levels at 12 weeks following randomization were compared in the trial arms using linear regression, adjusting for baseline values.

RESULTS

Of 1551 HIV-1-infected individuals screened for helminth infection, 299 were helminth infected. Two hundred and thirty-four adults were enrolled and underwent randomization and 208 individuals were included in intent-to-treat analyses. Mean CD4 cell count was 557 cells/microl and mean plasma viral load was 4.75 log10 copies/ml at enrollment. Albendazole therapy resulted in significantly higher CD4 cell counts among individuals with Ascaris lumbricoides infection after 12 weeks of follow-up (+109 cells/microl; 95% confidence interval +38.9 to +179.0, P = 0.003) and a trend for 0.54 log10 lower HIV-1 RNA levels (P = 0.09). These effects were not seen with treatment of other species of soil-transmitted helminths.

CONCLUSION

Treatment of A. lumbricoides with albendazole in HIV-1-coinfected adults resulted in significantly increased CD4 cell counts during 3-month follow-up. Given the high prevalence of A. lumbricoides infection worldwide, deworming may be an important potential strategy to delay HIV-1 progression.