Emergent canine visceral leishmaniasis in Argentina: Comparative diagnostics and relevance to proliferation of human disease.

BACKGROUND: Visceral leishmaniasis (VL) is a zoonotic protozoal vector-borne disease that is a major public health challenge. In Argentina, canine (CVL) and human visceral leishmaniasis (HVL) have recently emerged. There is a lack of standardised diagnostic tests for CVL, which hinders control of CVL and HVL. METHODOLOGY/PRINCIPAL FINDINGS: Sampling was carried out in Puerto Iguazú, Argentina, comprising 190 asymptomatic, oligosymptomatic and polysymptomatic dogs. The following diagnostics were applied: microscopy of lymph node aspirate (LNA); three immunochromatographic rapid diagnostic tests (RDTs), prototype rK28-ICT, rK39-ICT (both Coris BioConcept), commercial rK39 (InBios); ELISA for IgG, IgG1 and IgG2, against rK28, rK39 or crude lysate antigen. DNA detection and analysis, with 30 dogs, was of the ITS1 region using skin samples, and loop-mediated isothermal amplification (LAMP; Eiken Loopamp) of buffy coat, skin scrape or LNA. 15.4% of dogs were positive by LNA microscopy. The rK28 RDT had higher seropositivity rate (61%) than either a prototype rK39 RDT (31.4%) or commercial rK39 RDT (18.8%), without cross-reactivity with six other pathogens. IgG anti-rK39 ELISA antibody titres, but not IgG2, were positively correlated with number of clinical signs. LAMP with LNA had a higher positivity rate than PCR; buffy coat sampling was more sensitive than skin scrape. ITS1 confirmed Leishmania (Leishmania) infantum as the agent of CVL. Leishmania (Viannia) spp. was detected in skin samples from two dogs, compatible with Leishmania (Viannia) braziliensis. CONCLUSIONS/SIGNIFICANCE: Seroprevalence confirmed rapid increase in CVL in Puerto Iguazú. The rK28 RDT test potentially has great value for improved point-of-care diagnosis. Given cost reduction and accessibility, commercial LAMP may be applicable to buffy coat. RDT biomarkers of CVL clinical status are required to combat spread of CVL and HVL. The presence of Viannia, perhaps as an agent of human mucocutaneous leishmaniasis (MCL), highlights the need for vigilance and surveillance.

Epidemiological and molecular investigation of resurgent cutaneous leishmaniasis in Sudan.

OBJECTIVES: Local health personnel have drawn attention to an apparent increase in incidence and severity of cutaneous leishmaniasis (CL) in Sudan. The objective of this study was to investigate CL burden and surveillance. METHODS: Surveillance data were compiled from the KalaCORE programme, Leishmania coordinators in Northern Kordofan and Southern Darfur, and Khartoum Dermatology Hospital. CL lesions were sampled from 14 suspected cases from Northern Kordofan and the Hospital for Tropical Diseases in Omdurman. PCR-restriction fragment length polymorphism analysis and multilocus sequencing were used to characterize the disease agent. RESULTS: All sites reported substantial increases from 2014 to 2016/7, far exceeding World Health Organization case reports for 2014, consistent with a widespread outbreak. Single seasonal peak incidence was observed, except for two peaks in Southern Darfur. In Northern Kordofan, the odds ratio for CL in the 35-44 years age group was 2.6 times higher than in the >45 years age group (p<0.0001); in Southern Darfur, the OR was 2.38 greater in males than females (p<0.0001). Lesions included severe presentations, despite chemotherapy. Leishmania major was identified as the agent. CONCLUSIONS: Active surveillance is required to understand the extent of CL in Sudan, as well as training to standardize surveillance, diagnosis, reporting, and quality control. Point-of-care rapid diagnosis would be valuable. Genotyping and phenotyping are required to monitor the emergence of pathogenic strains, drug resistance, outbreaks, and changes in severity.

Effect of single-dose anthelmintic treatment during pregnancy on an infant's response to immunisation and on susceptibility to infectious diseases in infancy: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Helminth infections affect the human immune response. We investigated whether prenatal exposure to and treatment of maternal helminth infections affects development of an infant's immune response to immunisations and unrelated infections. METHODS: In this randomised, double-blind, placebo-controlled trial, we enrolled 2507 women in the second or third trimester of pregnancy who were planning to deliver in Entebbe General Hospital, Entebbe, Uganda. With a computer-generated random number sequence in blocks of 100, we assigned patients to 440 mg albendazole and 40 mg/kg praziquantel (n=628), 440 mg albendazole and a praziquantel-matching placebo (n=625), 40 mg/kg praziquantel and an albendazole-matching placebo (n=626), or an albendazole-matching placebo and praziquantel-matching placebo (n=628). All participants and hospital staff were masked to allocation. Primary outcomes were immune response at age 1 year to BCG, tetanus, and measles immunisation; incidence of infectious diseases during infancy; and vertical HIV transmission. Analysis was by intention-to-treat. This trial is registered, number ISRCTN32849447. FINDINGS: Data were available at delivery for 2356 women, with 2345 livebirths; 2115 (90%) of liveborn infants remained in follow-up at 1 year of age. Neither albendazole nor praziquantel treatments affected infant response to BCG, tetanus, or measles immunisation. However, in infants of mothers with hookworm infection, albendazole treatment reduced interleukin-5 (geometric mean ratio 0·50, 95% CI 0·30-0·81, interaction p=0·02) and interleukin-13 (0·52, 0·34-0·82, 0·0005) response to tetanus toxoid. The rate per 100 person-years of malaria was 40·9 (95% CI 38·3-43·7), of diarrhoea was 134·1 (129·2-139·2), and of pneumonia was 22·3 (20·4-24·4). We noted no effect on infectious disease incidence for albendazole treatment (malaria [hazard ratio 0·95, 95% CI 0·79-1.14], diarrhoea [1·06, 0·96-1·16], pneumonia [1·11, 0·90-1·38]) or praziquantel treatment (malaria [1·00, 0·84-1·20], diarrhoea [1·07, 0·98-1·18], pneumonia [1·00, 0·80-1·24]). In HIV-exposed infants, 39 (18%) were infected at 6 weeks; vertical transmission was not associated with albendazole (odds ratio 0·70, 95% CI 0·35-1·42) or praziquantel (0·60, 0·29-1·23) treatment. INTERPRETATION: These results do not accord with the recently advocated policy of routine antenatal anthelmintic treatment, and the value of such a policy may need to be reviewed. FUNDING: Wellcome Trust.

Effects of maternal and infant co-infections, and of maternal immunisation, on the infant response to BCG and tetanus immunisation.

Some vaccines show poor efficacy in tropical countries. Within a birth cohort in Uganda, we investigated factors that might influence responses to BCG and tetanus immunisation. Whole blood assay responses to crude culture filtrate proteins of Mycobacterium tuberculosis (cCFP)) and tetanus toxoid (TT) were examined among 1506 and 1433 one-year-olds, respectively. Maternal Mansonella perstans infection was associated with higher interleukin (IL)-10 responses to both immunogens but no reduction in gamma interferon (IFN-γ), IL-5 and IL-13 responses; other maternal helminth infections showed little effect. Tetanus immunisation during pregnancy was associated with higher infant responses to TT; maternal BCG scar (from past immunisation) with lower infant IL-5 and IL-13 responses to cCFP. IFN-γ, IL-5 and IL-13 to TT were reduced in HIV-exposed-uninfected infants; infant malaria and HIV were associated with lower IFN-γ, IL-5 and IL-13 responses to both immunogens. We conclude that maternal helminth infections are unlikely to explain poor vaccine efficacy in the tropics. Effects of maternal immunisation on infant responses to vaccines should be explored. Prevention of infant malaria and HIV could contribute to effectiveness of immunisation programmes.

Identifying sub-optimal responses to ivermectin in the treatment of River Blindness.

Identification of drug resistance before it becomes a public health concern requires a clear distinction between what constitutes a normal and a suboptimal treatment response. A novel method of analyzing drug efficacy studies in human helminthiases is proposed and used to investigate recent claims of atypical responses to ivermectin in the treatment of River Blindness. The variability in the rate at which Onchocerca volvulus microfilariae repopulate host's skin following ivermectin treatment is quantified using an individual-based onchocerciasis mathematical model. The model estimates a single skin repopulation rate for every host sampled, allowing reports of suboptimal responses to be statistically compared with responses from populations with no prior exposure to ivermectin. Statistically faster rates of skin repopulation were observed in 3 Ghanaian villages (treated 12-17 times), despite the wide variability in repopulation rates observed in ivermectin-naïve populations. Another village previously thought to have high rates of skin repopulation was shown to be indistinguishable from the normal treatment response. The model is used to generate testable hypotheses to identify whether atypical rates of skin repopulation by microfilariae could result from low treatment coverage alone or provide evidence of decreased ivermectin efficacy. Further work linking phenotypic poor responses to treatment with parasite molecular genetics markers will be required to confirm drug resistance. Limitations of the skin-snipping method for estimating parasite load indicates that changes in the distribution of microfilarial repopulation rates, rather than their absolute values, maybe a more sensitive indicator of emerging ivermectin resistance.

The impact of helminths on the response to immunization and on the incidence of infection and disease in childhood in Uganda: design of a randomized, double-blind, placebo-controlled, factorial trial of deworming interventions delivered in pregnancy and early childhood [ISRCTN32849447].

BACKGROUND: Helminths have profound effects on the immune response, allowing long-term survival of parasites with minimal damage to the host. Some of these effects "spill-over", altering responses to non-helminth antigens or allergens. It is suggested that this may lead to impaired responses to immunizations and infections, while conferring benefits against inflammatory responses in allergic and autoimmune disease. These effects might develop in utero, through exposure to maternal helminth infections, or through direct exposure in later life. PURPOSE: To determine the effects of helminths and their treatment in pregnancy and in young children on immunological and disease outcomes in childhood. METHODS: The trial has three randomized, double-blind, placebo-controlled interventions at two times, in two people: a pregnant woman and her child. Pregnant women are randomized to albendazole or placebo and praziquantel or placebo. At age 15 months their children are randomized to three-monthly albendazole or placebo, to continue to age five years. The proposed designation for this sequence of interventions is a 2 x 2(x2) factorial design. Children are immunized with BCG and against polio, Diphtheria, tetanus, Pertussis, Haemophilus, hepatitis B and measles. Primary immunological outcomes are responses to BCG antigens and tetanus toxoid in whole blood cytokine assays and antibody assays at one, three and five years of age. Primary disease outcomes are incidence of malaria, pneumonia, diarrhoea, tuberculosis, measles, vertical HIV transmission, and atopic disease episodes, measured at clinic visits and twice-monthly home visits. Effects on anaemia, growth and intellectual development are also assessed. CONCLUSION: This trial, with a novel design comprising related interventions in pregnant women and their offspring, is the first to examine effects of helminths and their treatment in pregnancy and early childhood on immunological, infectious disease and allergic disease outcomes. The results will enhance understanding of both detrimental and beneficial effects of helminth infection and inform policy.

Relation between chemokine receptor use, disease stage, and HIV-1 subtypes A and D: results from a rural Ugandan cohort.

OBJECTIVES: To determine whether there are differences in coreceptor use in subjects infected with HIV-1 envelope subtypes A and D that could explain the differences in progression rates between these subtypes in a rural Ugandan cohort. METHODS: HIV-1 was subtyped in env by V3 sequencing or heteroduplex mobility assay. Coreceptor use was determined by the ability of the isolates to replicate in U87 CD4 cells expressing different coreceptors. The Fisher exact test was used to examine the relation between coreceptor use and subtype, clinical stage, and V3 charge. The Kruskall-Wallis nonparametric test was used to examine the association between median CD4 cell counts, coreceptor use, and subtype. Logistic regression was used to examine predicted coreceptor use at different CD4 groupings. RESULTS: Isolates from 66 participants were analyzed. Thirty-one were infected with subtype A, and 35 were infected with subtype D. Although this work was based on a small sample size, we found statistically significant differences. The probability of having an X4 virus was higher in subtype D infections than in subtype A infections among those with a non-AIDS clinical status (Fisher exact test, P = 0.040). Logistic regression analysis, in which we predicted X4 use by subtype and stratified by CD4 group, confirmed these findings among those with a CD4 count >200 cells/microL (likelihood ratio test, P = 0.003). R5 viruses were associated with higher median CD4 cell counts than X4 or X4/R5 (Kruskall-Wallis test, P = 0.0045). A V3 charge of +5 and greater was highly associated with X4 virus (Fisher exact test, P = 0.006). CONCLUSIONS: These subtype differences in coreceptor use may partially explain the faster progression rates we have previously reported in individuals infected with subtype D compared with subtype A. Our observations may have implications for the future use of coreceptor inhibitors in this population.

The role of vertical transmission and health care-related factors in HIV infection of children: a community study in rural Uganda.

OBJECTIVES: To determine the probable route of transmission of HIV to children aged 12 years or younger in a rural area of Uganda from 1999 through 2000 and to examine associations between HIV infection and health care-related variables. METHODS: The HIV infections status for 6991 children was determined from 1 round of an ongoing population surveillance system, and the reported numbers of injections in the past year and blood transfusions were determined for 5922 of these children based on a medical questionnaire. Data from the surveillance system and from an additional survey were used to assess the potential for vertical infection from a mother to her child. RESULTS: The HIV prevalence among children was 0.4%. Of 23 definite and 4 probable cases of HIV infection in children, vertical transmission was not possible for 1 case, not likely for another case, and possibly not vertical for another case. The population-attributable fraction for vertical transmission was between 90% and 94%. Large numbers of injections in the past year and ever having a blood transfusion were only associated with HIV infection in children exposed to vertical transmission. CONCLUSIONS: Up to 10% of HIV infections in children in the study area were not attributable to vertical transmission, and thus were possibly attributable to iatrogenic transmission. Associations seen between health care-related variables and HIV were likely to be attributable to treatment for AIDS-related illness in children infected vertically.

A polymorphism that reduces RANTES expression is associated with protection from death in HIV-seropositive Ugandans with advanced disease.

We investigated the effect of RANTES polymorphisms on human immunodeficiency virus type 1 (HIV-1) disease progression in an urban population of Uganda. HIV-positive individuals homozygous for the INT1.1C polymorphism, which had been associated previously with low RANTES expression, were less likely to die than were those with other genotypes (hazard ratio, 0.53 [95% confidence interval, 0.33-0.83]; P=.007). This report of a non-human leukocyte antigen genetic association with HIV-1 and/or acquired immunodeficiency syndrome disease progression in an African population reveals a genetic effect different from that reported elsewhere for African Americans and may impact therapeutic strategies targeting the RANTES pathway in HIV infection.

Schistosoma mansoni, nematode infections, and progression to active tuberculosis among HIV-1-infected Ugandans.

Rates of tuberculosis (TB) in Africa are highest among people infected with HIV. Searching for additional risk factors in a cohort of HIV-infected Ugandan adults, we previously found that a type 2 cytokine bias and eosinophilia were associated with progression to active TB. A possible role for helminth infection was assessed in this study. We analyzed TB incidence in 462 members of this cohort who were screened for filarial infections, gastrointestinal nematodes, and schistosomiasis. Progression to TB was not associated with gastrointestinal nematodes (rate ratio [RR], 1.18; confidence intervals [CIs], 0.66-2.10) or Mansonella perstans (RR, 0.42; CI, 0.13-1.34). A weak association between Schistosoma mansoni infection and TB was found (RR, 1.42; CI, 0.86-2.34); after adjusting for potential explanatory variables and using more stringent diagnostic criteria, the association was strengthened (RR, 2.31; 1.00-5.33). This analysis suggests an effect of S. mansoni infection on progression to active TB among HIV-1-infected Ugandans.

Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies.

OBJECTIVE: To estimate the sex-specific effect of herpes simplex virus type 2 (HSV-2) on the acquisition of HIV infection. BACKGROUND: The increased number of longitudinal studies available since the last meta-analysis was published allows for the calculation of age- and sexual behaviour-adjusted relative risks (RR) separately for men and women. DESIGN: Systematic review and meta-analysis of longitudinal studies. METHODS: PubMed, Embase and relevant conference abstracts were systematically searched to identify longitudinal studies in which the relative timing of HSV-2 infection and HIV infection could be established. Where necessary, authors were contacted for separate estimates in men and women, adjusted for age and a measure of sexual behaviour. Summary adjusted RR were calculated using random-effects meta-analyses where appropriate. Studies on recent HSV-2 incidence as a risk factor for HIV acquisition were also collated. RESULTS: Of 19 eligible studies identified, 18 adjusted for age and at least one measure of sexual behaviour after author contact. Among these, HSV-2 seropositivity was a statistically significant risk factor for HIV acquisition in general population studies of men [summary adjusted RR, 2.7; 95% confidence interval (CI), 1.9-3.9] and women (RR, 3.1; 95% CI, 1.7-5.6), and among men who have sex with men (RR, 1.7; 95% CI, 1.2-2.4). The effect in high-risk women showed significant heterogeneity, with no overall evidence of an association. CONCLUSIONS: Prevalent HSV-2 infection is associated with a three-fold increased risk of HIV acquisition among both men and women in the general population, suggesting that, in areas of high HSV-2 prevalence, a high proportion of HIV is attributable to HSV-2.

A randomised controlled trial of the effects of albendazole in pregnancy on maternal responses to mycobacterial antigens and infant responses to Bacille Calmette-Guérin (BCG) immunisation [ISRCTN32849447].

BACKGROUND: Maternal schistosomiasis and filariasis have been shown to influence infant responses to neonatal bacille Calmette-Guérin (BCG) immunisation but the effects of maternal hookworm, and of de-worming in pregnancy, are unknown. METHODS: In Entebbe, Uganda, we conducted a randomised, double-blind, placebo-controlled trial of a single dose of 400 mg of albendazole in the second trimester of pregnancy. Neonates received BCG. Interferon-gamma (IFN-gamma) and interleukin (IL)-5 responses to a mycobacterial antigen (crude culture filtrate proteins (CFP) of Mycobacterium tuberculosis) were measured in a whole blood assay. We analysed results for binary variables using chi2 tests and logistic regression. We analysed continuous variables using Wilcoxon's tests. RESULTS: Maternal hookworm was associated with reduced maternal IFN-gamma responses to CFP (adjusted odds ratio for IFN-gamma > median response: 0.14 (95% confidence interval 0.02-0.83, p = 0.021). Conversely, maternal hookworm was associated with subsequent increased IFN-gamma responses in their one-year-old infants (adjusted OR 17.65 (1.20-258.66; p = 0.013)). Maternal albendazole tended to reduce these effects. CONCLUSION: Untreated hookworm infection in pregnancy was associated with reduced maternal IFN-gamma responses to mycobacterial antigens, but increased responses in their infants one year after BCG immunisation. The mechanisms of these effects, and their implications for protective immunity remain, to be determined.

Conjugate pneumococcal vaccine in HIV-infected Ugandans and the effect of past receipt of polysaccharide vaccine.

We investigated the immunogenicity of a 7-valent conjugate pneumococcal vaccine (CPV) in human immunodeficiency virus-infected Ugandan adults and measured the effect of past pneumococcal polysaccharide vaccine (PPV) receipt given as part of a controlled trial. Two doses of CPV, 4 weeks apart, were given to 54 past PPV recipients and 55 past placebo recipients (84% female; median CD4 cell count, 251 cells/ microL [range, 1-936 cells/ microL]). Postvaccination anticapsular immunoglobulin G (IgG) concentrations were directly correlated with CD4 cell count (P < .01 for all serotypes). There were significant increases in anticapsular IgG concentrations for all serotypes after the first dose (P < .01) and for all serotypes except 14 and 9V after the second dose. Past receipt of PPV did not affect vaccine response.

The effect of malaria on mortality in a cohort of HIV-infected Ugandan adults.

OBJECTIVES: To investigate the effects of malaria parasitaemia and clinical malaria on mortality in HIV seropositive and seronegative adults. METHODS: A cohort of adults in rural Uganda were followed from 1990 to 1998. Participants attended routine clinic visits every 3 months and also when sick (interim visits). Information was collected on HIV serostatus, history of fever, current fever and malaria parasite levels. Malaria was categorized as any parasitaemia, significant parasitaemia (>/=1.25 x 10(6) parasites/ml at routine or >/=50 parasites per 200 white blood cells at interim visits) or clinical malaria. The effect of malaria on all-cause mortality was assessed using Cox models. RESULTS: The 222 HIV seropositive participants made 2762 routine visits and 1522 interim visits. During follow-up, of the 211 participants with full records, 69% had at least one episode of parasitaemia, 51% experienced significant parasitaemia and 28% had clinical malaria. There were 90 deaths in 922 person-years of observation. There were no significant associations between numbers of visits with any parasitaemia, significant parasitaemia or clinical malaria on mortality rates. The highest mortality rates were observed in those making four or more routine visits with significant parasitaemia [adjusted mortality rate ratio (RR) 3.27 compared with those making 0 such visits; P=0.078] and those making two or more visits with clinical malaria (adjusted RR 2.23; P=0.093). There was no significant interaction between any malaria category and HIV serostatus. Conclusion We found no evidence of a strong detrimental effect of malaria on all-cause mortality in HIV seropositive adults in this setting.

HIV risk perception and prevalence in a program for prevention of mother-to-child HIV transmission: comparison of women who accept voluntary counseling and testing and those tested anonymously.

OBJECTIVE: To determine whether data from voluntary counseling and testing (VCT)/prevention of mother-to-child transmission (PMTCT) programs can be used for HIV surveillance. METHODS: Women attending an antenatal clinic at the district hospital in Entebbe, Uganda, from May 2002 to April 2003 were offered counseling and HIV testing with same-day results (VCT) and nevirapine for PMTCT was provided for HIV-positive women and their babies. Those who declined VCT were tested for HIV anonymously. RESULTS: Overall, 2635 women accepted VCT; 883 were tested anonymously. HIV prevalence was higher in VCT than in anonymously tested women in the first month of the program (20% vs. 11%, P=0.05) and in months with <70% VCT uptake (17% vs. 8%, P<0.001) but was similar in months with high uptake. Uptake of VCT was higher in women who had risk factors for HIV, especially those who believed themselves to have been exposed (84% vs. 73%, P<0.001). CONCLUSION: There was a bias to accepting VCT in women with HIV, or risk factors for HIV infection, the former most apparent when there was low coverage. Data from VCT/PMTCT programs cannot replace anonymous surveillance for monitoring of HIV epidemic trends where coverage is incomplete within clinics or communities.

Treatment of Schistosoma mansoni infection increases helminth-specific type 2 cytokine responses and HIV-1 loads in coinfected Ugandan adults.

BACKGROUND: Studies showing that helminths stimulate type 2 cytokine responses and influence responses to unrelated antigens suggest that helminths may accelerate human immunodeficiency virus type 1 (HIV-1) disease progression in coinfected individuals and that antihelminthic therapy may be beneficial. By the same logic, however, the increase in type 2 cytokines occurring immediately after antischistosomal treatment might increase viral replication and be detrimental. METHODS: To assess the effect of antischistosomal therapy on immune responses and HIV-1 replication, a cohort of 163 Ugandans coinfected with Schistosoma mansoni and HIV-1 was treated with praziquantel. CD4(+) T lymphocyte counts, eosinophil counts, and plasma HIV-1 RNA concentrations were measured before treatment and 1 month and 5 months after treatment. Schistosoma mansoni- and Mycobacterium tuberculosis-specific cytokine responses and serum interleukin (IL)-10 concentrations were analyzed. RESULTS: Transient increases in viral load and sustained decreases in CD4(+) T lymphocyte count were observed, especially in subjects with higher-intensity infections. Despite enhanced posttreatment S. mansoni-specific type 2 responses, no increase in eosinophils or in M. tuberculosis-specific type 2 responses nor any decline in M. tuberculosis-specific interferon (IFN)-gamma responses were seen. A significant decline in circulating IL-10 concentrations was observed. CONCLUSION: Although the mechanisms underlying the increase in viral load after treatment with praziquantel are unclear, these results do not support the hypothesis that treating schistosomiasis is beneficial in the management of HIV-1 disease in Africa.