Urinary interleukins (IL)-6 and IL-10 in schoolchildren from an area with low prevalence of Schistosoma haematobium infections in coastal Kenya

Urinary cytokines are gaining traction as tools for assessing morbidity in infectious and non-infectious inflammatory diseases of the urogenital tract. However, little is known about the potential of these cytokines in assessing morbidity due to S. haematobium infections. Factors that may influence the urinary cytokine levels as morbidity markers also remain unknown. Therefore the objective of the present study was to assess how urinary interleukins (IL-) 6 and 10 are associated with gender, age, S. haematobium infections, haematuria and urinary tract pathology and; 2) to assess the effects of urine storage temperatures on the cytokines. This was a cross-sectional study in 2018 involving 245 children aged 5-12 years from a S. haematobium endemic area of coastal Kenya. The children were examined for S. haematobium infections, urinary tract morbidity, haematuria and urinary cytokines (IL-6 and IL-10). Urine specimens were also stored at -20°C, 4°C or 25°C for 14 days before being assayed for IL6 and IL-10 using ELISA. The overall prevalence of S. haematobium infections, urinary tract pathology, haematuria, urinary IL-6 and urinary IL-10 were 36.3%, 35.8%, 14.8%, 59.4% and 80.5%, respectively. There were significant associations between prevalence of urinary IL-6, but not IL-10, and age, S. haematobium infection and haematuria (p = 0.045, 0.011 and 0.005, respectively) but not sex or ultrasound-detectable pathology. There were significant differences in IL-6 and IL-10 levels between urine specimens stored at -20°C and those stored at 4°C (p<0.001) and, between those stored at 4°C and those stored at 25°C (p<0.001). Urinary IL-6, but not IL-10, was associated with children's age, S. haematobium infections and haematuria. However, both urinary IL-6 and IL-10 were not associated with urinary tract morbidity. Both IL-6 and IL-10 were sensitive to urine storage temperatures.

HIV infections among female sex workers in Mombasa, Kenya: current prevalence and trends over 25 years

Over 20 years, interventions have targeted HIV among female sex workers (FSWs) in Kenya given their central role in new infections. To determine the effects of these interventions, we assessed the prevalence and correlates of HIV among a random sample of FSWs and modelled prevalence estimates from studies since 1993. FSWs aged 16-34 years were enrolled through multi-stage sampling. Regression models identified correlates of HIV infection. Generalised linear mixed modelling estimated temporal changes in prevalence between 1993 and 2016. 882 FSWs were enrolled. Prevalence rose from 3.6% among 16-20-year-olds to 31.6% among 31-34-year-old FSWs. Those aged 31 to 34 years had greater odds of HIV compared to those 16 to 20 years (AOR 14.2, 95% CI, 5.5-36.8). Infection was less prevalent among FSWs with tertiary education compared to those with primary or no education (AOR 0.23, 95% CI, 0.07-0.78). There was an overall 30% reduction in prevalence from 1993 to 2016 with an average annual decline of 3%. About one in ten FSWs in Mombasa are currently infected with HIV. Considering FSWs' central role in sustaining population-level infections, these initiatives require continued support, focusing on reducing transmission from older FSWs and those with less education.

Types and prevalence of HIV-related opportunistic infections/conditions among HIV-positive patients attending Kenyatta National Hospital in Nairobi, Kenya

Background

Although antiretroviral therapy (ART) has resulted in significant decrease in opportunistic infections (OIs), OIs continue to cause significant morbidity and mortality among HIV patients.

Objective

To determine the prevalence and types of HIV/AIDS-related OIs among patients attending Kenyatta National Hospital (KNH) in Nairobi, Kenya.

Methods

A cross-sectional study was conducted from May to August 2010 among patients ≥19 years. An interviewer-administered questionnaire was used to collect data on socio-demographic factors, HIV and OIs. CD4 data were extracted from clinical records.

Results

Most patients (72%) had lived with HIV for ≤ 5 years and 78.8% had an OI. The 3 most common OIs were TB (35%), Herpes Zoster (HZ; 15.4%) and oral thrush (OT; 8%). Years of HIV infection significantly predicted TB (p=0.01). Patients with CD4 ≤ 349 were almost twice as likely to have TB, than those with CD4 ≥500. Type of occupation predicted OT (p=0.04) with skilled workers less likely to have OT. Patients with primary/vocational/technical education were >3 times more likely to have HZ than those with tertiary education.

Conclusion

Due to the complex management of HIV and its associated OIs, appropriate implementation of the recommended guidelines for care and prevention among patients at KNH is important.

Intimate partner violence among HIV-positive women in Nairobi, Kenya

Purpose

This study was conducted to identify the prevalence and sociodemographic factors associated with four forms of intimate partner violence (IPV) among HIV-positive women attending the Comprehensive Care Centre at the Kenyatta National Hospital in Nairobi, Kenya.

Methods

A cross-sectional study was conducted among 600 sexually active HIV-positive women aged 18–69 years from May to August of 2012. A structured questionnaire including questions pertaining to sociodemographic characteristics, health care decisions, and forms of IPV (controlling behavior, emotional abuse, physical violence, and sexual violence) was administered to each woman.

Results

All women reported experiencing emotional abuse; 20%, 17%, and 15% experienced controlling behavior, physical violence, and sexual violence, respectively. Women who reported low/below average socioeconomic status (SES) had a greater likelihood of experiencing controlling behavior than women with high/average SES (adjusted odds ratio [aOR] =1.62, 95% CI 1.05–2.51). Women who were unemployed had greater odds of experiencing physical violence than those who were employed (aOR =2.35, 95% CI 1.31–4.23). Non-Christian women had higher odds of experiencing controlling behavior, physical violence, and sexual violence than Christian women (aOR =4.41, 95% CI 1.81–10.76 and aOR =3.33, 95% CI 1.43–7.80).

Conclusion

Based on the prevalence of IPV and the sociodemographic factors identified to be associated with IPV among women in this study it may be beneficial to include IPV screening as part of routine clinic visits for HIV-positive and other women. Furthermore, women who report emotional abuse or controlling behavior from spouse should not be overlooked, as these two forms of IPV may precede or accompany physical and sexual IPV. Women who report experiencing IPV during clinic visits may be referred to organizations and resources available to battered women in Kenya. Increased funding for anti-IPV programs and changes in policy may also contribute to a reduction in IPV among HIV-positive and other women in Kenya.

Bridging antimicrobial resistance knowledge gaps: The East African perspective on a global problem

Background

There is worldwide concern of rapidly increasing antimicrobial resistance (AMR). However, there is paucity of resistance surveillance data and updated antibiograms in Africa in general. This study was undertaken in Kenyatta National Hospital (KNH) -the largest public tertiary referral centre in East & Central Africa—to help bridge existing AMR knowledge and practice gaps.

Methods

A retrospective review of VITEK 2 (bioMérieux) records capturing antimicrobial susceptibility data for the year 2015 was done and analysed using WHONET and SPSS.

Results

Analysis of 624 isolates revealed AMR rates higher than most recent local and international reports. 88% of isolates tested were multi-drug resistant (MDR) whereas 26% were extensively-drug resistant (XDR). E. coli and K. pneumoniae had poor susceptibility to penicillins (8–48%), cephalosporins (16–43%), monobactams (17–29%), fluoroquinolones (22–44%) and trimethoprim-sulfamethoxazole (7%). Pseudomonas aeruginosa and Acinetobacter baumanii were resistant to penicillins and cephalosporins, with reduced susceptibility to carbapenems (70% and 27% respectively). S aureus had poor susceptibility to penicillins (3%) and trimethoprim-sulfamethoxazole (29%) but showed excellent susceptibility to imipenem (90%), vancomycin (97%) and linezolid (99%).

Conclusions

The overwhelming resistance to commonly used antibiotics heralds a clarion call towards strengthening antimicrobial stewardship programmes and regular AMR regional surveillance.

Risk factors for ocular surface squamous neoplasia in Kenya: a case-control study

OBJECTIVE

To determine modifiable risk factors of ocular surface squamous neoplasia (OSSN) in Kenya using disease-free controls.

METHODS

Adults with conjunctival lesions were recruited at four eye care centres in Kenya and underwent excision biopsy. An equal number of controls having surgery for conditions not affecting the conjunctiva and unrelated to ultraviolet light were group-matched to cases by age group, sex and eye care centre. Associations of risk factors with OSSN were evaluated using multivariable logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). Continuous variables were compared using the t-test or the Wilcoxon-Mann-Whitney U-test depending on their distribution.

RESULTS

A total of 131 cases and 131 controls were recruited. About two-thirds of participants were female, and the mean age of cases and controls was 42.1 years and 43.3 years, respectively. Risk factors for OSSN were HIV infection without antiretroviral therapy (ART) use (OR = 48.42; 95% CI: 7.73-303.31) and with ART use (OR = 19.16; 95% CI: 6.60-55.57), longer duration of exposure to the sun in the main occupation (6.9 h/day vs. 4.6 h/day, OR = 1.24; 95% CI: 1.10-1.40) and a history of allergic conjunctivitis (OR = 74.61; 95% CI: 8.08-688.91). Wearing hats was protective (OR = 0.22; 95% CI: 0.07-0.63).

CONCLUSION

Measures to prevent and control HIV, reduce sun exposure such as wearing hats and control allergic conjunctivitis are recommended.

Toluidine Blue 0.05% Vital Staining for the Diagnosis of Ocular Surface Squamous Neoplasia in Kenya

IMPORTANCE

Clinical features are unreliable for distinguishing ocular surface squamous neoplasia (OSSN) from benign conjunctival lesions.

OBJECTIVE

To evaluate the adverse effects, accuracy, and interobserver variation of toluidine blue 0.05% vital staining in distinguishing OSSN, confirmed by histopathology, from other conjunctival lesions.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study in Kenya from July 2012 through July 2014 of 419 adults with suspicious conjunctival lesions. Pregnant and breastfeeding women were excluded.

EXPOSURES

Comprehensive ophthalmic slitlamp examination was conducted. Vital staining with toluidine blue 0.05% aqueous solution was performed before surgery. Initial safety testing was conducted on large tumors scheduled for exenteration looking for corneal toxicity on histology before testing smaller tumors. We asked about pain or discomfort after staining and evaluated the cornea at the slitlamp for epithelial defects. Lesions were photographed before and after staining.

MAIN OUTCOMES AND MEASURES

Diagnosis was confirmed by histopathology. Six examiners assessed photographs from a subset of 100 consecutive participants for staining and made a diagnosis of OSSN vs non-OSSN. Staining was compared with histopathology to estimate sensitivity, specificity, and predictive values. Adverse effects were enumerated. Interobserver agreement was estimated using the κ statistic.

RESULTS

A total of 143 of 419 participants (34%) had OSSN by histopathology. The median age of all participants was 37 years (interquartile range, 32-45 years) and 278 (66%) were female. A total of 322 of the 419 participants had positive staining while 2 of 419 were equivocal. There was no histological evidence of corneal toxicity. Mild discomfort was reported by 88 (21%) and mild superficial punctate keratopathy seen in 7 (1.7%). For detecting OSSN, toluidine blue had a sensitivity of 92% (95% CI, 87%-96%), specificity of 31% (95% CI, 25%-36%), positive predictive value of 41% (95% CI, 35%-46%), and negative predictive value of 88% (95% CI, 80%-94%). Interobserver agreement was substantial for staining (κ = 0.76) and moderate for diagnosis (κ = 0.40).

CONCLUSIONS AND RELEVANCE

With the high sensitivity and low specificity for OSSN compared with histopathology among patients with conjunctival lesions, toluidine blue 0.05% vital staining is a good screening tool. However, it is not a good diagnostic tool owing to a high frequency of false-positives. The high negative predictive value suggests that a negative staining result indicates that OSSN is relatively unlikely.

Schistosoma haematobium and soil-transmitted Helminths in Tana Delta District of Kenya: infection and morbidity patterns in primary schoolchildren from two isolated villages

BACKGROUND

Schistosomes and soil-transmitted helminths (STH) (hookworm, Trichuris trichiura and Ascaris lumbricoides) are widely distributed in developing countries where they infect over 230 million and 1.5 billion people, respectively. The parasites are frequently co-endemic and many individuals are co-infected with two or more of the species, but information on how the parasites interact in co-infected individuals is scarce. The present study assessed Schistosoma haematobium and STH infection and morbidity patterns among school children in a hyper-endemic focus in the Tana River delta of coastal Kenya.

METHODS

Two hundred and sixty-two children aged 5-12 years from two primary schools were enrolled in the study. For each child, urine was examined for S. haematobium eggs and haematuria, stool was examined for STH eggs, peripheral blood was examined for eosinophilia and haemoglobin level, the urinary tract was ultrasound-examined for S. haematobium-related pathology, and the height and weight was measured and used to calculate the body mass index (BMI).

RESULTS

Prevalences of S. haematobium, hookworm, T. trichiura and A. lumbricoides infection were 94, 81, 88 and 46 %, respectively. There was no significant association between S. haematobium and STH infection but intensity of hookworm infection significantly increased with that of T. trichiura. Lower BMI scores were associated with high intensity of S. haematobium (difference =-0.48, p > 0.05) and A. lumbricoides (difference =-0.67, p < 0.05). Haematuria (both macro and micro) was common and associated with S. haematobium infection, while anaemia was associated with high intensity of S. haematobium (OR = 2.08, p < 0.05) and high hookworm infections OR = 4.75; p < 0.001). The majority of children had eosinophilia, which was significantly associated with high intensity of hookworm infection (OR = 5.34, p < 0.05). Overall 38 % of the children had ultrasound-detectable urinary tract morbidity, which was associated with high intensity of S. haematobium infection (OR = 3.13, p < 0.05).

CONCLUSION

Prevalences of S. haematobium and STH infections among the primary school children were high and the parasites were responsible for significant morbidity. A clear synergistic interaction was observed between hookworm and T. trichiura infections. Increased coverage in administration of praziquantel and albendazole in the area is recommended to control morbidity due to these infections.

ANTIBIOTIC SUSCEPTIBILITY OF ORGANISMS CAUSING URINARY TRACT INFECTION IN PATIENTS PRESENTING AT KENYATTA NATIONAL HOSPITAL, NAIROBI

BACKGROUND

Changes in susceptibility patterns of bacterial pathogens isolated from urinary tract infections emphasize the need for regional surveillance to generate information that can be used in management of patients. Knowledge on the current status of antimicrobial resistance in uropathogens, and the prevalence of expanding spectrum beta-lactamases (ESBLs) in the isolates will guide policy formulations and encourage prudent use of antimicrobials.

OBJECTIVE

Identify bacterial pathogens causing UTI and determine the association between the pathogens isolated from patients attending KNH. Determine antimicrobial susceptibility patterns of the UTI pathogens and the prevalence of ESBL in the isolated pathogens.

DESIGN

Laboratory-based study.

SETTING

Department of Medical Microbiology University of Nairobi and Kenyatta National Hospital microbiology laboratory, Nairobi, Kenya.

SUBJECTS

Nine hundred and forty eight patients presenting directly to the Kenyatta National Hospital's diagnostic lab. Patients were only classified as in-patients if at the time of specimen collection they were being admitted to one of KNH wards.

RESULTS

Out of the 948 urine samples processed, 189 in-patients and 37 out-patients samples had significant bacterial growth. The uropathogens identified from in-patient specimens were Escherichia coli (56), Klebsiellapneumoniae (33), Enterococcus spp. (34) and Entrobacter (16) making up 30%, 18%, 18% and 9% respectively. ESBL isolates were found to be resistant to the locally administered antibiotics; Augmentin (37%), Levofloxacin (37%), Cefoperazone (37%), Ampicillin (39%), Doxycyline (41%), Gentamicin (30%) and Nalidixic Acid (38%).

CONCLUSION

The increased prevalence of multidrug resistant ESBL pathogens poses challenges for health care providers at KNH and signifies the need for new approach to treat UTI. It would be prudent for laboratories to include specialized tests for detection of ESBL producing pathogens from isolates obtained from in-patients. Further studies on the mechanisms and pathways utilized by these bacteria to cause UTI will highlight other avenues in patient management.

Urinary cytokines in Schistosoma haematobium-infected schoolchildren from Tana Delta District of Kenya

BACKGROUND

Pathological changes due to infection with Schistosoma haematobium include cytokine-mediated urinary tract inflammation. The involved cytokines may be excreted in urine and their presence in urine may therefore reflect S. haematobium-related urinary tract pathology. The present study, for the first time, reports on the relationship between selected cytokines in urine and infection with S. haematobium in children from an area highly affected by this parasite.

METHODS

Children aged 5-12 years from two primary schools in Tana Delta District of Kenya were examined for S. haematobium eggs using urine filtration technique, for haematuria using dipstix and for eosinophil cationic protein (ECP), IL-6, IFN- γ, TNF-α and IL-10 levels using ELISA, and for S. haematobium-related urinary tract pathology using ultrasonography. In addition, venous blood was examined for serum IL-6, IFN- γ, TNF-α and IL-10 levels using ELISA.

RESULTS

There was no significant correlation between urinary and serum levels of IL-6, IFN- γ, TNF-α or IL-10. There was no significant difference in geometric mean intensity (GMI) in any of the serum cytokines, or in urinary TNF-α or IFN-γ, between children with light and heavy S. haematobium infections. However, children with heavy S. haematobium infections had significantly higher GMI of urinary IL-6 (p < 0.001) and lower GMI of urinary IL-10 (p = 0.002) than children with light infections. There was also a significant positive correlation between urinary IL-6 and urinary ECP (p < 0.001) and a significant negative correlation between urinary IL-10 and urinary ECP (p = 0.012).

CONCLUSION

Urinary IL-6 was positively correlated to and IL-10 was negatively correlated to infection intensity and urinary tract inflammation in S. haematobium-infected children. Urinary IL-6 and IL-10 ELISA may be a useful non-invasive tool to complement the already available tools for studying S. haematobium-related urinary tract pathology in children.

Pregnancy rates among female participants in phase I and phase IIA AIDS vaccine clinical trials in Kenya

BACKGROUND

Female participants in AIDS candidate vaccine clinical trials must agree to use effective contraception to be enrolled into the studies, and for a specified period after vaccination, since the candidate vaccines' effects on the embryo or foetus are unknown.

OBJECTIVES

To review data on female participants' pregnancy rates from phase I and IIA AIDS vaccine clinical trials conducted at the Kenya AIDS Vaccine Initiative (KAVI) and to discuss the challenges of contraception among female participants.

DESIGN

Descriptive observational retrospective study.

SETTING

KAVI clinical trial site, Kenyatta National Hospital and University of Nairobi, Kenya.

SUBJECTS

Thirty nine female participants were enrolled into these trials. They received family planning counselling and were offered a choice of different contraceptive methods, as per the protocols. All contraception methods chosen by the participants were offered at the study site at no cost to the participant.

RESULTS

Four women conceived during the study period when pregnancies were to be avoided. All four had opted for sexual abstinence as a contraceptive method, but reported having been coerced by their partners to have unprotected sexual intercourse.

CONCLUSION

Abstinence is clearly not a reliable contraceptive option for women in developing-country settings. Effective female-controlled contraceptives, administered at the clinical trial site, may empower female participants to better control their fertility, leading to more complete clinical trial data.

European and Developing Countries Clinical Trials Partnership (EDCTP): the path towards a true partnership

BACKGROUND

European and Developing Countries Clinical Trials Partnership (EDCTP) was founded in 2003 by the European Parliament and Council. It is a partnership of 14 European Union (EU) member states, Norway, Switzerland, and Developing Countries, formed to fund acceleration of new clinical trial interventions to fight the human immunodeficiency virus and acquired immune deficiency syndrome (HIV/AIDS), malaria and tuberculosis (TB) in the sub-Saharan African region. EDCTP seeks to be synergistic with other funding bodies supporting research on these diseases.

METHODS

EDCTP promotes collaborative research supported by multiple funding agencies and harnesses networking expertise across different African and European countries. EDCTP is different from other similar initiatives. The organisation of EDCTP blends important aspects of partnership that includes ownership, sustainability and responds to demand-driven research. The Developing Countries Coordinating Committee (DCCC); a team of independent scientists and representatives of regional health bodies from sub-Saharan Africa provides advice to the partnership. Thus EDCTP reflects a true partnership and the active involvement and contribution of these African scientists ensures joint ownership of the EDCTP programme with European counterparts.

RESULTS

The following have been the major achievements of the EDCTP initiative since its formation in 2003; i) increase in the number of participating African countries from two to 26 in 2008 ii) the cumulative amount of funds spent on EDCTP projects has reached 150 m euros, iii) the cumulative number of clinical trials approved has reached 40 and iv) there has been a significant increase number and diversity in capacity building activities.

CONCLUSION

While we recognise that EDCTP faced enormous challenges in its first few years of existence, the strong involvement of African scientists and its new initiatives such as unconditional funding to regional networks of excellence in sub-Saharan Africa is envisaged to lead to a sustainable programme. Current data shows that the number of projects supported by EDCTP is increasing. DCCC proposes that this success story of true partnership should be used as model by partners involved in the fight against other infectious diseases of public health importance in the region.

Immunoepidemiology of Wuchereria bancrofti infection in two East African communities: antibodies to the microfilarial sheath and their role in regulating host microfilaraemia

The response pattern of specific antibodies to the microfilarial sheath (sheath-Ab) of the mosquito-borne filarial parasite Wuchereria bancrofti was investigated in individuals from two East African communities with different levels of endemicity. Individuals from both communities presented a strong inverse relationship between positivity for sheath-Ab and being positive for microfilariae (mf) and circulating filarial antigens (CFA). The prevalence of sheath-Ab positivity was highest in young individuals, but peaked at a younger age in the high (1-14 years) than the low (15-19 years) endemicity community. IgG1, IgG2, IgG3 and IgE intensities to a crude adult filarial worm antigen were higher, and IgG4 intensities were lower, in sheath-Ab positive than in sheath-Ab negative individuals, probably reflecting the infection status of individuals. From the study it appears that individuals become sheath-Ab positive before mf and/or CFA can be detected in the peripheral blood, and only after later disappearance of sheath-Ab from the circulation can CFA and mf be diagnosed. In light of the findings, possible roles of the distinct sheath-Ab in the host-parasite relationship are discussed, and a hypothesis is proposed which suggests that sheath-Ab play an important role in the regulation of host microfilaraemia.

Immunoepidemiology of Wuchereria bancrofti infection: parasite transmission intensity, filaria-specific antibodies, and host immunity in two East African communities

We compared the age profiles of infection and specific antibody intensities in two communities with different transmission levels in East Africa to examine the contribution of humoral responses to human immunity to the vector-borne helminth Wuchereria bancrofti. The worm intensities were higher and exhibited a nonlinear age pattern in a high-transmission community, Masaika, in contrast to the low but linearly increasing age infection profile observed for a low-transmission community, Kingwede. The mean levels of specific immunoglobulin G1 (IgG1), IgG2, IgG4, and IgE were also higher in Masaika, but intriguingly, the IgG3 response was higher in Kingwede. The age-antibody patterns differed in the two communities but in a manner apparently contrary to a role in acquired immunity when the data were assessed using simple correlation methods. By contrast, multivariate analyses showed that the antibody response to infection may be classified into three types and that two of these types, a IgG3-type response and a response measuring a trade-off in host production of IgG4 and IgG3 versus production of IgG1, IgG2, and IgE, had a negative effect on Wuchereria circulating antigen levels in a manner that supported a role for these responses in the generation of acquired immunity to infection. Mathematical modeling supported the conclusions drawn from empirical data analyses that variations in both transmission and worm intensity can explain community differences in the age profiles and impacts of these antibody response types. This study showed that parasite-specific antibody responses may be associated with the generation of acquired immunity to human filarial infection but in a form which is dependent on worm transmission intensity and interactions between immune components.

Initiation of antiretroviral therapy leads to a rapid decline in cervical and vaginal HIV-1 shedding

BACKGROUND

Antiretroviral therapy (ART) may decrease HIV-1 infectivity in women by reducing genital HIV-1 shedding.

OBJECTIVES

To evaluate the time course and magnitude of decay in cervical and vaginal HIV-1 shedding as women initiate ART.

METHODS

This prospective, observational study of 20 antiretroviral-naive women initiating ART with stavudine, lamivudine, and nevirapine measured HIV-1 RNA in plasma, cervical secretions, and vaginal secretions. Qualitative polymerase chain reaction estimated HIV-1 DNA in cervical and vaginal samples. Perelson's two-phase viral decay model and non-linear random effects were used to compare RNA decay rates. Decreases in proviral DNA were evaluated using logistic regression and generalized estimating equations.

RESULTS

Significant decreases in the quantity of HIV-1 RNA were observed by day 2 in plasma (P < 0.001), day 2 in cervical secretions (P = 0.001), and day 4 in vaginal secretions (P < 0.001). Modeled initial and subsequent RNA decay rates in plasma, cervical secretions, and vaginal secretions were 0.6, 0.8, and 1.2 log10 virions/day, and 0.04, 0.05, and 0.06 log10 virions/day, respectively. The initial decay rate for vaginal HIV-1 RNA was more rapid than for plasma RNA (P = 0.02). Detection of HIV-1 DNA decreased significantly in vaginal secretions during the first week (P < 0.001). At day 28, 10 women had detectable HIV-1 RNA or proviral DNA in genital secretions.

CONCLUSIONS

Genital HIV-1 shedding decreased rapidly after ART initiation, consistent with a rapid decrease in infectivity. However, incomplete viral suppression in half of these women may indicate an ongoing risk of transmission.

Filarial-specific antibody response in East African bancroftian filariasis: effects of host infection, clinical disease, and filarial endemicity

The effect of host infection, chronic clinical disease, and transmission intensity on the patterns of specific antibody responses in Bancroftian filariasis was assessed by analyzing specific IgG1, IgG2, IgG3, IgG4, and IgE profiles among adults from two communities with high and low Wuchereria bancrofti endemicity. In the high endemicity community, intensities of the measured antibodies were significantly associated with infection status. IgG1, IgG2, and IgE were negatively associated with microfilaria (MF) status, IgG3 was negatively associated with circulating filarial antigen (CFA) status, and IgG4 was positively associated with CFA status. None of the associations were significantly influenced by chronic lymphatic disease status. In contrast, IgG1, IgG2, and IgG4 responses were less vigorous in the low endemicity community and, except for IgG4, did not show any significant associations with MF or CFA status. The IgG3 responses were considerably more vigorous in the low endemicity community than in the high endemicity one. Only IgG4 responses exhibited a rather similar pattern in the two communities, being significantly positively associated with CFA status in both communities. The IgG4:IgE ratios were higher in infection-positive individuals than in infection-negative ones, and higher in the high endemicity community than in the low endemicity one. Overall, these results indicate that specific antibody responses in Bancroftian filariasis are more related to infection status than to chronic lymphatic disease status. They also suggest that community transmission intensity play a dominant but subtle role in shaping the observed response patterns.

The effect of eight half-yearly single-dose treatments with DEC on Wuchereria bancrofti circulating antigenaemia

The effect of eight half-yearly treatment rounds with diethylcarbamazine (DEC; 6mg/kg bodyweight) on Wuchereria bancrofti-specific circulating filarial antigen (CFA), a marker of adult worm infection, was followed in 79 individuals who were CFA-positive before start of treatment. Half of these were also microfilariae (mf)-positive. Microfilaraemia decreased rapidly after onset of treatment and became undetectable after four treatments. Circulating antigenaemia also decreased progressively, but at a much slower rate. After two, four and eight treatment rounds, the mean CFA intensity was reduced by 81, 94 and 98%, and the prevalence of CFA positivity was 85, 66 and 57%, compared with pre-treatment, respectively. CFA clearance rates were negatively related to pre-treatment CFA intensities, and were higher among pre-treatment mf-negative individuals than among pre-treatment mf-positive individuals. Even among patients who had pre-treatment CFA intensities above the upper measuring level (32000antigen units), and who continued to have intensities above this level after treatment, a decrease in post-treatment CFA intensities was obvious from a continuous decrease in ELISA optical density values. Repeated DEC therapy thus appears to have a slow but profound and persistent macrofilaricidal effect, which in the long run may be beneficial to populations undergoing DEC-based control interventions by reducing the probability of future morbidity development.

The effect of repeated half-yearly diethylcarbamazine mass treatment on Wuchereria bancrofti infection and transmission in two East African communities with different levels of endemicity

The effect of repeated half-yearly mass treatment with diethylcarbamazine (DEC, 6 mg/kg body weight) on infection and transmission of Wuchereria bancrofti was assessed and compared in communities with high and low endemicity in eastern Africa, with pretreatment microfilaria (mf) and circulating filarial antigen (CFA) prevalences of 29.4% and 53.2% in the high endemicity community and 3.1% and 18.7% in the low endemicity community, respectively. Human infection was monitored by repeated cross-sectional surveys, and transmission by weekly light trap collection of vector mosquitoes in selected houses in each community. Treatments resulted in a progressive decrease in microfilaremia and circulating antigenemia in both communities, with relative reductions being considerably higher for mf than for CFA. Among pretreatment mf-positive individuals, more than 60% were diagnosed as mf negative and mean mf intensities were reduced by 99% in both communities after two treatment rounds. In contrast, only moderate reductions were seen in circulating antigenemia among pretreatment CFA-positive individuals, with mean intensities still being 24-39% of pretreatment values after two treatment rounds. Among the pretreatment mf/CFA-positive individuals, clearance to a CFA-negative status was negligible. Complete CFA clearance was only observed among pretreatment CFA-positive but mf negative individuals who also had much lower initial mean CFA levels than the mf-positive individuals. After treatment, the intensity of transmission decreased in the high-endemicity community, but this appeared mainly to be a consequence of a drought-induced reduction in vector density rather than to reduced mf load in the human population, since the proportion of mosquitoes carrying infective larvae was not reduced. No change in transmission or mosquito infectivity was observed after treatment in the low-endemicity community. Implications of these observations for the control of Bancroftian filariasis are discussed.

Filaria dance sign and subclinical hydrocoele in two east African communities with bancroftian filariasis

During population-wide cross-sectional surveys for Wuchereria bancrofti microfilaremia, circulating antigenaemia, and clinical disease in a high and a low endemicity community in East Africa in 1998, a portable ultrasound scanner was used simultaneously to examine the scrotal tissue of the male populations (n = 422 and 328, respectively) for signs of adult worms. The overall microfilaria (mf) and circulating filarial antigen (CFA) prevalences in the scanned males were 30.8% and 53.6% in the high and 4.3% and 19.8% in the low endemicity community, respectively. During ultrasound examination, the filaria dance sign (FDS)--indicating the presence of live adult W. bancrofti worms--was observed in 16.1% and 6.7% of the males in these communities, respectively. This examination also revealed that subclinical hydrocoele (fluid accumulation in the scrotal sac, not detected during physical examination for clinical hydrocoele) was very common, affecting 25.3% and 15.5% of the examined males in the high and low endemicity community, respectively. Both of these ultrasonographic signs started to appear around the age of puberty and were most common in adults. In the high endemicity community, the prevalence and mean intensity of mf and CFA were considerably higher in FDS-positive than in FDS-negative adult males, whereas no obvious difference in these parameters was noted between adult males with and without subclinical or the combination of clinical and subclinical hydrocoele. Associations were less clear in the low endemicity community, probably because of the low number of infected individuals. The application of ultrasonography as a tool in bancroftian filariasis epidemiological field studies thus indicated that scrotal pathology may be much more common in endemic areas than hitherto reported.

Bancroftian filariasis infection, disease, and specific antibody response patterns in a high and a low endemicity community in East Africa

Bancroftian filariasis infection, disease and specific antibody response patterns in a high and a low endemicity community in East Africa were analyzed and compared to assess the relationship between these parameters and community transmission intensity. Overall prevalences of microfilaremia and circulating filarial antigenemia were 24.9% and 52.2% in the high and 2.7% and 16.5% in the low endemicity community, respectively. A positive history of acute attacks of adenolymphangitis was given by 12.2% and 7.1% of the populations, 4.0% and 0.9% of the adult (> or = 20 years old) individuals presented with limb lymphedema, and 25.3% and 5.3% of the adult males had hydrocele, in the high and the low endemicity community, respectively. Both infection and disease appeared earlier and reached much higher levels in the high than in the low endemicity community. The observed overall and age-specific infection and disease patterns in the two communities were in agreement with the view that these are primarily shaped by transmission intensity. No statistically significant relationships between infection status of fathers and mothers and that of their children were observed in any of the communities for either microfilaremia or for circulating filarial antigenemia. The overall levels (prevalence and geometric mean intensity) of filarial-specific IgG1, IgG2, IgG4, and IgE were significantly higher in the high endemicity community than in the low endemicity dommunity. Surprisingly, the opposite pattern was found for IgG3. Community transmission intensity thus appears to be an important determinant of observed inter-community variation in infection, disease, and host response patterns in Bancroftian filariasis.

A simple and quick method for enhanced detection of specific IgE in serum from lymphatic filariasis patients

A new simple and quick technique, using a suspension of protein A agarose beads to absorb IgG4 from sera prior to determination of filarial-specific IgE in ELISA, is presented. The optimal ratio between serum and absorbant was determined by absorbing fixed volumes of sera from individuals from a Wuchereria bancrofti endemic area with different volumes of the protein A agarose bead suspension and testing supernatants for filaria-specific IgG4 and IgE. The effect of absorption on measured IgG4 and IgE intensities in sera from various categories of individuals from the endemic area was thereafter examined. Overall, absorption resulted in a 96.5% decrease in mean ELISA OD values for IgG4 and a 41.6% increase in mean ELISA OD values for IgE. Higher increases in IgE measurements were seen with sera from circulating filarial antigen (CFA) negative individuals (64.7%), microfilaria (mf) negative individuals (56.1%) and individuals with chronic filarial disease (62.7%) than with sera from individuals who were CFA positive (23.4%), mf positive (10.0%), or without chronic disease (36.5%). These differences indicate that the degree to which IgE detection in unabsorbed serum is blocked by IgG4 varies with infection and disease status. Absorption of IgG4 from serum with a protein A agarose bead suspension prior to measurement of specific IgE is a useful alternative to conventional gel column absorption methods, particularly when processing many samples.

Transmission intensity and the immunoepidemiology of bancroftian filariasis in East Africa

Previous attempts to determine the interactions between filariasis transmission intensity, infection and chronic disease have been limited by a lack of a theoretical framework that allows the explicit examination of mechanisms that may link these variables at the community level. Here, we show how deterministic mathematical models, in conjunction with analyses of standardized field data from communities with varying parasite transmission intensities, can provide a particularly powerful framework for investigating this topic. These models were based on adult worm population dynamics, worm initiated chronic disease and two major forms of acquired immunity (larval- versus adult-worm generated) explicitly linked to community transmission intensity as measured by the Annual Transmission Potential (ATP). They were then fitted to data from low, moderate and moderately high transmission communities from East Africa to determine the mechanistic relationships between transmission, infection and observed filarial morbidity. The results indicate a profound effect of transmission intensity on patent infection and chronic disease, and on the generation and impact of immunity on these variables. For infection, the analysis indicates that in areas of higher parasite transmission, community-specific microfilarial rates may increase proportionately with transmission intensity until moderated by the generation of herd immunity. This supports recent suggestions that acquired immunity in filariasis is transmission driven and may be significant only in areas of high transmission. In East Africa, this transmission threshold is likely to be higher than an ATP of at least 100. A new finding from the analysis of the disease data is that per capita worm pathogenicity could increase with transmission intensity such that the prevalences of both hydrocele and lymphoedema, even without immunopathological involvement, may increase disproportionately with transmission intensity. For lymphoedema, this rise may be further accelerated with the onset of immunopathology. An intriguing finding is that there may be at least two types of immunity operating in filariasis: one implicated in anti-infection immunity and generated by past experience of adult worms, the other involved in immune-mediated pathology and based on cumulative experience of infective larvae. If confirmed, these findings have important implications for the new global initiative to achieve control of this disease.

Wuchereria bancrofti in a community with seasonal transmission: stability of microfilaraemia, antigenaemia and filarial-specific antibody concentrations

The effect of seasonal transmission on microfilaraemia, antigenaemia and filarial-specific antibody levels in individuals infected with Wuchereria bancrofti was investigated in a follow-up study in an endemic community in north-eastern Tanzania. The subjects were 37 adult male residents who were found to be positive for circulating filarial antigen (CFA) at the beginning of the study (26 of whom were also found microfilaraemic with W. bancrofti at this time). Blood samples were collected from each subject in July 1998, January 1999 and July 1999, during the seasons when transmission intensity was high, low and high, respectively. The mean intensities of microfilaraemia and the mean concentrations of CFA were each slightly higher during the low-transmission season than during the two high-transmission seasons but the differences were not statistically significant (P > 0.05). Similarly, the mean levels of filarial-specific IgG1, IgG2, IgG3, IgG4 or IgE did not differ to a statistically significant degree between the three examination times. Microfilaraemias and the levels of CFA and filarial-specific antibodies all therefore appeared to be remarkably stable and largely unaffected by the seasonal variation in transmission. That no variation in the mean IgG4/IgE ratio was observed over the study period may indicate that the level of resistance to W. bancrofti infection in the study subjects was also unaffected by the transmission season.

Praziquantel side effects during treatment of Schistosoma mansoni infected pupils in Kibwezi, Kenya

Four hundred and thirty six pupils in two primary schools in Kibwezi, Kenya aged between seven and sixteen years and positive for S. mansoni were treated as follows: 320 pupils with a single dose of praziquantel at 40 mg/kg body weight and 116 controls with a placebo. Immediate and delayed side effects of praziquantel were observed. The main side-effects were abdominal pain (36.3%), headache (35.3%) and nausea (13.1%). There was correlation between frequencies of these side-effects and intensity of infection measured as eggs per gram of faeces. Other side-effects included dizziness (9.7%), fever (7.8%), urticaria and bloody diarrhoea. Overall, the side-effects of praziquantel were mild and transient, and did not require any intervention. For ethical reasons, all pupils who served as controls were treated with praziquantel after the study.

Loa loa antigen detection by ELISA: a new approach to diagnosis

Circulating immune complexes associated Loa loa antigen in sera of 27 subjects with Loa loa (13 'occult' and 14 microfilaraemic infections) was detected with Polyethylene glycol enzyme linked immunosorbent assay (PEG-ELISA) in a controlled study. Loa loa antigen was detected in all 27 sera. There was no correlation between antigen levels and microfilaraemia density. Cross reaction with Mansonella perstans was found. Although this serological test is able to detect all Loa loa infections, its use is limited by cross reaction with other filariasis. It is hoped that sensitivity will be improved by using monoclonal antibodies.