The effect of three-monthly albendazole treatment on Th2 responses: Differential effects on IgE and IL-5

Treatment of pregnant mice with ABZ had no effect on the immune response of their offspring infected with Trichinella spiralis

Trichinellosis is a food-borne parasitic disease with a worldwide distribution that not only endangers human health but also leads to economic loss. Infection of pregnant animals with Trichinella spiralis (T. spiralis) may lead to abortion and other adverse consequences, so it is necessary to treat the infection during pregnancy. Albendazole (ABZ) is an effective therapeutic drug for adult T. spiralis worms. The safety of this drug during pregnancy, especially whether it has any effect on offspring, should be fully evaluated. A change in the immune response to T. spiralis in the offspring of pregnant mice treated with ABZ may lead to a difference in susceptibility to T. spiralis compared to that of the offspring of normal mice. However, the safety of ABZ treatment in pregnant mice and the effects on the immune response and susceptibility of their offspring to T. spiralis are poorly understood. Therefore, we assessed whether maternal ABZ treatment during pregnancy affects the immune response or susceptibility to T. spiralis in infected offspring. In this study, mice were infected with T. spiralis at 10 days of pregnancy and treated with ABZ at 3 days post infection (dpi), and the specific immune response in the pregnant mice and the survival rate and worm burden of their 6-week-old offspring after T. spiralis infection were examined. The results showed that the antiparasitic immune response in pregnant mice was activated by T. spiralis infection. Treatment of pregnant mice with ABZ increased the percentage of CD4 + T cells. The percentages of Th2 and Treg cells in the PP, MLN and spleen of pregnant mice in the infection group were significantly increased compared with those of normal mice. ABZ treatment during pregnancy promoted the Th2 and Treg immune responses in pregnant mice infected with T. spiralis. The transcriptional levels of the Th2 and Treg cytokines IL-4, IL-5, IL-13, and TGF-β in the small intestine, MLN and spleen of pregnant mice in the treatment group were significantly higher than those of pregnant mice in the T. spiralis infection only group. The results indicated that ABZ treatment did not cause abortion in pregnant mice or affect the survival rate of their offspring. Furthermore, treatment of pregnant mice with ABZ had no significant effect on the above immune responses in their T. spiralis-infected offspring compared to those of T. spiralis-infected offspring of mice in the normal group. The results also indicated that treatment of pregnant mice infected with T. spiralis with ABZ shifted the immune response to a Th2- and Treg-skewed immune response and that this drug had no effects on the offspring survival rate, immune response or worm burden after T. spiralis infection. This study further indicated that ABZ administration to treat T. spiralis infection in pregnant mice is safe for the select immune response and susceptibility of their offspring.

Immunological Considerations for Schistosoma Vaccine Development: Transitioning to Endemic Settings

Despite mass drug administration programmes with praziquantel, the prevalence of schistosomiasis remains high. A vaccine is urgently needed to control transmission of this debilitating disease. As some promising schistosomiasis vaccine candidates are moving through pre-clinical and clinical testing, we review the immunological challenges that these vaccine candidates may encounter in transitioning through the clinical trial phases in endemic settings. Prior exposure of the target population to schistosomes and other infections may impact vaccine response and efficacy and therefore requires considerable attention. Schistosomes are known for their potential to induce T-reg/IL-10 mediated immune suppression in populations which are chronically infected. Moreover, endemicity of schistosomiasis is focal whereby target and trial populations may exhibit several degrees of prior exposure as well as in utero exposure which may increase heterogeneity of vaccine responses. The age dependent distribution of exposure and development of acquired immunity, and general differences in the baseline immunological profile, adds to the complexity of selecting suitable trial populations. Similarly, prior or concurrent infections with other parasitic helminths, viral and bacterial infections, may alter immunological responses. Consequently, treatment of co-infections may benefit the immunogenicity of vaccines and may be considered despite logistical challenges. On the other hand, viral infections leave a life-long immunological imprint on the human host. Screening for serostatus may be needed to facilitate interpretation of vaccine responses. Co-delivery of schistosome vaccines with PZQ is attractive from a perspective of implementation but may complicate the immunogenicity of schistosomiasis vaccines. Several studies have reported PZQ treatment to induce both transient and long-term immuno-modulatory effects as a result of tegument destruction, worm killing and subsequent exposure of worm antigens to the host immune system. These in turn may augment or antagonize vaccine immunogenicity. Understanding the complex immunological interactions between vaccine, co-infections or prior exposure is essential in early stages of clinical development to facilitate phase 3 clinical trial design and implementation policies. Besides well-designed studies in different target populations using schistosome candidate vaccines or other vaccines as models, controlled human infections could also help identify markers of immune protection in populations with different disease and immunological backgrounds.

Prevalence of Toxocara and Toxascaris infection among human and animals in Iran with meta-analysis approach

BACKGROUND

Toxocariasis is a worldwide zoonotic parasitic disease caused by species of Toxocara and Toxascaris, common in dogs and cats. Herein, a meta-analysis was contrived to assess the prevalence of Toxocara/Toxascaris in carnivore and human hosts in different regions of Iran from April 1969 to June 2019.

METHODS

The available online articles of English (PubMed, Science Direct, Scopus, and Ovid) and Persian (SID, Iran Medex, Magiran, and Iran Doc) databases and also the articles that presented in held parasitology congresses of Iran were involved.

RESULTS

The weighted prevalence of Toxocara/Toxascaris in dogs (Canis familiaris) and cats (Felis catus) was 24.2% (95% CI: 18.0-31.0%) and 32.6% (95% CI: 22.6-43.4%), respectively. Also, pooled prevalence in jackal (Canis aureus) and red fox (Vulpes vulpes) was 23.3% (95% CI: 7.7-43.2%) and 69.4% (95% CI: 60.3-77.8%), correspondingly. Weighted mean prevalence of human cases with overall 28 records was 9.3% (95% CI: 6.3-13.1%). The weighted prevalence of Toxocara canis, Toxocara cati, and Toxascaris leonina was represented as 13.8% (95% CI: 9.8-18.3%), 28.5% (95% CI: 20-37.7%) and 14.3% (95% CI: 8.1-22.0%), respectively.

CONCLUSION

Our meta-analysis results illustrate a considerable prevalence rate of Toxocara/Toxascaris, particularly in cats and dogs of northern parts of Iran. The presence of suitable animal hosts, optimum climate and close contact of humans and animals would have been the reason for higher seroprevalence rates of human cases in our region. Given the significance clinical outcomes of human Toxocara/Toxascaris, necessary measures should be taken.

Public health deworming programmes for soil-transmitted helminths in children living in endemic areas

BACKGROUND

The World Health Organization (WHO) recommends treating all school children at regular intervals with deworming drugs in areas where helminth infection is common. Global advocacy organizations claim routine deworming has substantive health and societal effects beyond the removal of worms. In this update of the 2015 edition we included six new trials, additional data from included trials, and addressed comments and criticisms.

OBJECTIVES

To summarize the effects of public health programmes to regularly treat all children with deworming drugs on child growth, haemoglobin, cognition, school attendance, school performance, physical fitness, and mortality.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; Embase; LILACS; the metaRegister of Controlled Trials (mRCT); reference lists; and registers of ongoing and completed trials up to 19 September 2018.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs that compared deworming drugs for soil-transmitted helminths (STHs) with placebo or no treatment in children aged 16 years or less, reporting on weight, height, haemoglobin, and formal tests of cognition. We also sought data on other measures of growth, school attendance, school performance, physical fitness, and mortality.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials for inclusion, risk of bias, and extracted data. We analysed continuous data using the mean difference (MD) with 95% confidence intervals (CIs). Where data were missing, we contacted trial authors. We stratified the analysis based on the background burden of STH infection. We used outcomes at time of longest follow-up. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We identified 51 trials, including 10 cluster-RCTs, that met the inclusion criteria. One trial evaluating mortality included over one million children, and the remaining 50 trials included a total of 84,336 participants. Twenty-four trials were in populations categorized as high burden, including nine trials in children selected because they were helminth-stool positive; 18 with intermediate burden; and nine as low burden.First or single dose of deworming drugsFourteen trials reported on weight after a single dose of deworming drugs (4970 participants, 14 RCTs). The effects were variable. There was little or no effect in studies conducted in low and intermediate worm burden groups. In the high-burden group, there was little or no effect in most studies, except for a large effect detected from one study area in Kenya reported in two trials carried out over 30 years ago. These trials result in qualitative heterogeneity and uncertainty in the meta-analysis across all studies (I² statistic = 90%), with GRADE assessment assessed as very low-certainty, which means we do not know if a first dose or single dose of deworming impacts on weight.For height, most studies showed little or no effect after a single dose, with one of the two trials in Kenya from 30 years ago showing a large average difference (2621 participants, 10 trials, low-certainty evidence). Single dose probably had no effect on average haemoglobin (MD 0.10 g/dL, 95% CI 0.03 lower to 0.22 higher; 1252 participants, five trials, moderate-certainty evidence), or on average cognition (1596 participants, five trials, low-certainty evidence). The data are insufficient to know if there is an effect on school attendance and performance (304 participants, one trial, low-certainty evidence), or on physical fitness (280 participants, three trials, very low-certainty evidence). No trials reported on mortality.Multiple doses of deworming drugsThe effect of regularly treating children with deworming drugs given every three to six months on weight was reported in 18 trials, with follow-up times of between six months and three years; there was little or no effect on average weight in all but two trials, irrespective of worm prevalence-intensity. The two trials with large average weight gain included one in the high burden area in Kenya carried out over 30 years ago, and one study from India in a low prevalence area where subsequent studies in the same area did not show an effect. This heterogeneity causes uncertainty in any meta-analysis (I² = 78%). Post-hoc analysis excluding trials published prior to 2000 gave an estimate of average difference in weight gain of 0.02 kg (95%CI from 0.04 kg loss to 0.08 gain, I² = 0%). Thus we conclude that we do not know if repeated doses of deworming drugs impact on average weight, with a fewer older studies showing large gains, and studies since 2000 showing little or no average gain.Regular treatment probably had little or no effect on the following parameters: average height (MD 0.02 cm higher, 95% CI 0.09 lower to 0.13 cm higher; 13,700 participants, 13 trials, moderate-certainty evidence); average haemoglobin (MD 0.01 g/dL lower; 95% CI 0.05 g/dL lower to 0.07 g/dL higher; 5498 participants, nine trials, moderate-certainty evidence); formal tests of cognition (35,394 participants, 8 trials, moderate-certainty evidence); school performance (34,967 participants, four trials, moderate-certainty evidence). The evidence assessing an effect on school attendance is inconsistent, and at risk of bias (mean attendance 2% higher, 95% CI 5% lower to 8% higher; 20,650 participants, three trials, very low-certainty evidence). No trials reported on physical fitness. No effect was shown on mortality (1,005,135 participants, three trials, low-certainty evidence).

AUTHORS' CONCLUSIONS

Public health programmes to regularly treat all children with deworming drugs do not appear to improve height, haemoglobin, cognition, school performance, or mortality. We do not know if there is an effect on school attendance, since the evidence is inconsistent and at risk of bias, and there is insufficient data on physical fitness. Studies conducted in two settings over 20 years ago showed large effects on weight gain, but this is not a finding in more recent, larger studies. We would caution against selecting only the evidence from these older studies as a rationale for contemporary mass treatment programmes as this ignores the recent studies that have not shown benefit.The conclusions of the 2015 edition have not changed in this update.

BCG scar, socioeconomic and nutritional status: a study of newborns in urban area of Makassar, Indonesia

Objective

To investigate factors that determine the response to Bacille Calmette–Guérin (BCG) vaccination in urban environments with respect to socioeconomic status (SES), prenatal exposure to infections or newborn's nutritional status.

Methods

The study was conducted in an urban area, in Makassar, Indonesia. At baseline, 100 mother and newborns pair from high and low SES communities were included. Intestinal protozoa, soil transmitted helminths, total IgE, anti‐Hepatitis A Virus IgG and anti‐Toxoplasma IgG were measured to determine exposure to infections. Information on gestational age, birth weight/height and delivery status were collected. Weight‐for‐length z‐score, a proxy for newborns adiposity, was calculated. Leptin and adiponectin from cord sera were also measured. At 10 months of age, BCG scar size was measured from 59 infants. Statistical modelling was performed using multiple linear regression.

Results

Both SES and birth nutritional status shape the response towards BCG vaccination at 10 months of age. Infants born to low SES families have smaller BCG scar size compared to infants born from high SES families and total IgE contributed to the reduced scar size. On the other hand, infants born with better nutritional status were found to have bigger BCG scar size but this association was abolished by leptin levels at birth.

Conclusion

This study provides new insights into the importance of SES and leptin levels at birth on the development of BCG scar in 10 months old infants.

Deworming in non-pregnant adolescent girls and adult women: a systematic review and meta-analysis

BACKGROUND

The impact of deworming on parasite load, nutritional status and other health outcomes of non-pregnant adolescent girls and adult women is uncertain.

METHODS

MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, the WHO International Clinical Trials Registry Platform, the Cochrane Database of Systematic Reviews and Food and Technology Abstracts databases were searched until 24 September 2018. Studies were included if they were randomised controlled trials (RCTs), controlled before and after studies or interrupted time studies comparing deworming with no intervention or placebo in non-pregnant adolescent girls and women 10 to 49 years old. Outcomes of interest included parasite load, reinfection, anaemia, severe anaemia, iron deficiency, diarrhoea or all-cause morbidity. Risk of bias was assessed using the Cochrane risk of bias tool.

RESULTS

We included four RCTs of mass deworming involving 1086 participants, in the analyses. Mass deworming probably reduces the prevalence of roundworm infection (RR 0.29; 95% CI 0.14 to 0.62; 2 trials; 1498 participants, moderate certainty evidence), prevalence of hookworm infection (RR 0.32; 95% CI 0.18 to 0.59; 2 trials; 1498 participants, moderate certainty evidence), prevalence of whipworm infection (RR 0.77; 95% CI 0.65 to 0.91; 2 trials; 1498 participants, moderate certainty evidence) compared to the control group. Deworming may make little or no difference in prevalence of anaemia (RR 0.82; 95% CI 0.60 to 1.11, 3 studies, 683 participants, low certainty evidence) and prevalence of iron-deficiency (RR 0.89; 95% CI 0.64 to 1.23, 1 study, 186 participants, low certainty evidence) compared to control. We are uncertain whether deworming reduces the prevalence of severe anaemia compared to control as the certainty of evidence was very low. None of the included studies assessed screen and treat deworming or reported reinfection, diarrhoea or adverse events.

CONCLUSIONS

Mass deworming probably reduces the prevalence of soil-transmitted helminth infections but may have little or no effect on anaemia and iron-deficiency in adolescent girls and non-pregnant women in comparison to no intervention or placebo. We are uncertain about the effect on severe anaemia. These results are limited by sparse data and the moderate to very low quality of evidence available.

SYSTEMATIC REVIEW REGISTRATION

The protocol was registered in PROSPERO (registration number: CRD42016039557 ).  Primary source of funding: Evidence and Programme Guidance unit, Department of Nutrition for Health and Development, World Health Organization (WHO).

Prevalence of Atopy following Mass Drug Administration with Albendazole: A Study in School Children on Flores Island, Indonesia

BACKGROUND

In many rural areas of tropical countries such as Indonesia, the prevalence of soil-transmitted helminths (STH) infections remains high. At the same time, the burden of allergic disorders in such rural areas is reported to be low and inversely associated with helminth infections. To reduce the morbidity and transmission of helminth infections, the world health organization recommends preventive treatment of school children by providing mass drug administration (MDA) with albendazole. Here, we had an opportunity to evaluate the prevalence of skin reactivity to allergens before and after albendazole treatment to get an indication of the possible impact of MDA on allergic sensitization.

METHODS

A study was conducted among 150 school children living in an area endemic for STH infections. Before and 1 year after anthelminthic treatment with albendazole, stool samples were examined for the presence of STH eggs, skin prick tests (SPT) for cockroach and house dust mites were performed, blood eosinophilia was assessed, and total immunoglobulin E (IgE) and C-reactive protein (CRP) were measured in plasma.

RESULTS

Anthelminthic treatment significantly reduced the prevalence of STH from 19.6 before treatment to 6% after treatment (p < 0.001). Levels of total IgE (estimate: 0.30; 95% CI 0.22-0.42, p < 0.0001), CRP (estimate: 0.60; 95% CI 0.42-0.86, p = 0.006), and eosinophil counts (estimate: 0.70; 95% CI 0.61-0.80, p < 0.001) decreased significantly. The prevalence of SPT positivity increased from 18.7 to 32.7%. Multivariate analysis adjusted for confounding factors showed an increased risk of being SPT positive to any allergen (OR 3.04; 95% CI 1.338-6.919, p = 0.008).

CONCLUSIONS

This study indicates that 1 year of MDA with albendazole was associated with a reduced prevalence of STH infections. This study shows that the prevalence of allergic sensitization increases after 1 year of albendazole treatment. Placebo-controlled and larger studies are needed to further substantiate a role of deworming treatment in an increased risk of allergic sensitization.

The relationship between treatment for Strongyloides stercoralis infection and type 2 diabetes mellitus in an Australian Aboriginal population: A three-year cohort study

AIM

To determine the effect of treatment for Strongyloides stercoralis infection on type 2 diabetes mellitus in an Australian Aboriginal population.

METHODS

A three-year cohort study of 259 Aboriginal adults living in northern Australia. Subjects were tested for S. stercoralis infection, diabetic status and HbA1c at recruitment. 92 subjects were ELISA positive for S. stercoralis and 91 were treated with two doses of ivermectin 0.2mg/kg. Serological cure was assessed after 6months and those who remained positive were retreated. All subjects then underwent the same testing at 3years follow up.

RESULTS

Follow up was successful in 80% of subjects. Eight new cases of T2DM were recorded, 7 in the treatment group and 1 in the non-treatment group (Unadjusted RR 7.71, CI 0.98-60.48, p=0.052. Adjusted RR 5.45, CI 075-35.92, p=0.093). In addition, worsening glycemic control (T2DM or newly diagnosed glucose intolerance) was recorded in 13 cases (10 treatment group, 3 non treatment. Adjusted RR 3.74, CI 1.06-13.20, p=0.04). There was a significant improvement in glycemic control in the patients with pre-existing T2DM when treated for S. stercoralis compared to the non-treatment group (Diff. -1.03, p=0.009).

CONCLUSION

This study demonstrated a differential effect of treatment for S. stercoralis on glucose metabolism in patients with and without T2DM. It showed a significant effect on the development of T2DM and glucose intolerance in those without T2DM, while improving glycemic control in subjects with pre-existing T2DM. Although numbers in this study are small, it suggests that larger studies may be of interest.