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The ICT card test to detect circulating filarial antigen and an ELISA that detects filaria-specific urinary IgG[sub 4] were each used to screen 473 subjects from a community in Sri Lanka where Wuchereria bancrofti is endemic. When the ICT test was used as the gold standard, the ELISA was found to have a sensitivity of 91.2%. However, far more of the subjects were found ELISA-positive than ICT-positive (76.5% v. 31.1%). The youngest children studied (aged 1-10 years) were similar to the adult subjects in terms of the prevalence of antigenaemia (33.8%) and the prevalence (72.1%) and concentration of filaria-specific IgG[sub 4] in their urine. Therefore, especially as urine samples are easier, less painful and safer to collect than blood samples, the ELISA may be particularly useful to screen very young and school-age children, to estimate current levels of transmission in a particular area. [ABSTRACT FROM AUTHOR]

The prevalence of Wuchereria bancrofti antigenaemia determined in 353 subjects in Matara, Sri Lanka by Og4C3 ELISA was 20.7%. Positive rates obtained with the same subjects by 1 ml Nuclepore filtration and 60 µl thick blood smear were 11.3% and 7.9%, respectively. Antigen levels were positively associated with microfilaria counts. Two-thirds of antigen-positive and microfilaria-negative (Ag+/Mf-) individuals were > 25-year-old, but younger age groups (≤ 25-year-old) tended to have proportionally more Ag+/Mf- cases. Possible origins of the Ag+/Mf- status are discussed. [ABSTRACT FROM AUTHOR]

In visceral and mucocutaneous leishmaniasis, humoral immune response can reflect disease severity and parasite burden. Cutaneous leishmaniasis (CL) in Sri Lanka is caused by a usually visceralizing parasite, Leishmania donovani. We assessed the parasite burden (relative quantity-RQ) in 190 CL patients using quantitative real-time PCR (qPCR-with primers designed for this study) and smear microscopy, then correlated it with clinical parameters and IgG response. RQ of parasite DNA was determined with human-specific glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as the internal control. The qPCR sensitivity was tested with serially diluted DNA from cultured L. donovani parasites. Smears were assigned a score based on number of parasites per high power field. Data from previous studies were used for comparison and correlation; nested Internal Transcribed Spacer 1 (ITS1) PCR as reference standard (RS) and IgG antibody titers to the Leishmania rKRp42 antigen as the immune response. The qPCR amplified and quantified 86.8% of the samples while demonstrating a fair and significant agreement with ITS1-PCR and microscopy. Parasite burden by qPCR and microscopy were highly correlated (r = 0.76; p = 0.01) but showed no correlation with the IgG response (r = 0.056; p = 0.48). Corresponding mean RQs of IgG titers grouped by percentiles, showed no significant difference (p = 0.93). Mean RQ was higher in early lesions (p = 0.04), decreased with lesion size (p = 0.12) and slightly higher among papules, nodules and wet ulcers (p = 0.72). Our study established qPCR's efficacy in quantifying parasite burden in Sri Lankan CL lesions but no significant correlation was observed between the parasite burden and host IgG response to the Leishmania rKRP42 antigen., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Lymphatic filariasis (LF) has been declared eliminated in Sri Lanka in September 2016. To maintain elimination status, a surveillance system to detect hidden endemic foci or LF resurgence is of highest priority. In this paper, we have reported an investigation of LF transmission in Trincomalee district where a surveillance program was not carried out due to 30 years of civil unrest. Proposed surveillance system included, measurement of anti-filarial IgG4 in urine of schoolchildren in areas where LF transmission could exist and assessment of circulating filarial antigen (CFA) and microfilaria (mf) in all urine antibody positive schoolchildren, their family members and 10-15 neighbours of each urine antibody positive household. Spatial distribution of the anti-filarial antibody titers in urine in a high antibody suspected area was analyzed using GPS logger data. Among 2301 school children from 11 schools studied, 41 (1.8%) urine antibody positives were found. The antibody positive rates of the schools ranged between 0 and 4.0%. Nine of the 630 (1.4%) examined became positive for CFA but were negative for mf. Although there were no mf positives, positive CFA and antibody results indicated the existence of Wuchereria bancrofti in Trincomalee. Highest antibody titres in an area correlated with the prevalences of urine antibodies and CFA. Spatial analysis showed LF transmission foci. Therefore, a combination of the non-invasive methods, urine ELISA and GPS mapping, will be a new effective surveillance system to identify hidden LF transmission foci., (Copyright © 2018. Published by Elsevier B.V.)

Alleviating morbidity due to lymphatic filariasis (LF)-especially in elderly patients who are rather ignorant-is presently the biggest challenge for the national filariasis campaign. We introduced two follow-up schemes and compared each other to address three key programmatic issues (1) locating patients, (2) educating patients, family members on practice of lymphoedema self-care (3) well sustained daily self-care. Hundred and seven lymphoedema patients were introduced to the new Community Home Based Care (CHBC) programme as a part of MMDP programme at their homes. Twenty seven of 107 patients were selected by purposive sampling and followed-up under two schemes, 14 in Daily follow-up (DFU) scheme and 13 in Monthly follow-up (MFU) scheme. Impact was assessed using a KAP score, number of entry lesions (EL) and number of ADL episodes, limb volume, its appearance, changes in the quality of life and gained benefits. Visiting patients in their homes to introduce lymphoedema care programme was a success. KAP scores of the more important activities on lymphoedema care were significantly higher in DFU scheme. Number of patients (51.9%; 14/27) who had EL/s at baseline reduced significantly to 18.5% (5/27) at one year follow-up. The mean numbers of ADL episodes/year reduced significantly in both schemes. Six photographs of 27 showed obvious improvement in lymphoedema and its grade. Mean volume of lymphoedema reduced significantly in both schemes at one year no significant difference between schemes. Benefit score at one year revealed that the patients in DFU scheme received significantly higher amount of benefits compared to MFU scheme. In conclusion daily instruction has significantly motivated the patient and his/her family bringing a new hope., (Copyright © 2017 Elsevier B.V. All rights reserved.)

For the declaration of elimination of lymphatic filariasis, reliable epidemiological data in all parts of a country are required. In Sri Lanka, due to social disturbance, there are 3 provinces whose endemicity has been declared unknown. Further, a recent report revealed an endemic pocket, which is on the border with the district that was not covered by the national elimination program. These facts indicate the necessity of more extensive studies to discover hidden endemic foci. To facilitate such studies, we evaluated 2 methods of Rapid Assessment Procedure (RAP) in Hambantota district, where the filariasis endemicity was low: (1) indirect questioning by mailing a questionnaire to each local leader (IndQ), asking about the presence of clinical cases, and (2) focus group discussion (FGD) by villagers. The information given by people was validated with clinical examination by doctors (CE) and IgG4 ELISA using urine samples. In the results: there was a strong positive correlation between CE and ELISA rates. The hydrocele rates obtained by FGD or IndQ were associated significantly with CE rates. The rates by FGD or Cluster-IndQ ('modified' IndQ) were also associated significantly with ELISA rates. The IndQ was most cost-effective. Based on these findings, we have concluded that screening by IndQ and confirmation by the ELISA would be an effective and practical way in Sri Lanka to locate endemic foci in hitherto unsurveyed districts., (© 2013 Elsevier Ireland Ltd. All rights reserved.)

ELISA for filaria-specific IgG4 in urine (urine ELISA) was applied to children in 7 schools in Sri Lanka, before and after 5 rounds of annual mass drug administration (MDA). The pre-treatment IgG4 prevalence in 2002 was 3.20%, which decreased to 0.91% in 2003 after the first MDA (P<0.001), and finally to 0.36% in 2007 after the 5th MDA. Among 5-10 year-old children, the prevalence decreased from 3.37% in 2002 to 0.51% in 2003 (P=0.009). A pattern of IgG4 titer distribution according to age and its yearly change could also provide useful information in drug efficacy analysis. In 2008, new samples from eleven 2006/07 urine ELISA-positive students and their family members (total n=56) were examined by ICT antigen test, microfilaria test, and urine ELISA. No infection was confirmed among them. Urine ELISA will be useful in monitoring elimination/resurgence in a post-MDA low endemic situation., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

To eliminate lymphatic filariasis by means of mass drug administration, it is essential to have reliable data on the disease distribution and prevalence in targeted areas. In Matara district, Sri Lanka, self-administered questionnaires were mailed to 2105 local leaders questioning the presence and the numbers of elephantiasis and hydrocele cases. The information provided by them revealed that elephantiasis was clearly aggregated in the southern part of the district along the coast, while hydrocele was distributed rather evenly in the whole district, including Deniyaya region where no endemic filariasis had been known. To confirm active transmission of filariasis in Deniyaya, Wuchereria bancrofti antigen and filaria-specific urinary IgG4 antibody were measured with 2436 subjects. The positive rates for antigen and antibody were 0.6% and 4.3%, respectively. The titer analysis of IgG4 according to age revealed that the youngest IgG4 positive was 3 years old, and that in 10 years old or less, there were 16 positives out of 607 children examined (2.6%). It was concluded that filarial transmission at a low level was going on in the region.

A total of 14 Sri Lankan pregnant women, who were anti-Brugia pahangi urinary IgG4 positive, and their 14 newborn babies were followed up for the urinary antibody for 2 years by enzyme-linked immunosorbent assay. Eight babies showed positive IgG4 reaction, at least once within 4 months after birth. Urinary antibody titers of mothers and their babies measured around the perinatal period showed a significant positive correlation, suggesting that baby's IgG4 was transferred from the mother through the placenta. The IgG4 decreased gradually and became negative in all positive babies by day 339.3 after birth. The present result provides a basis to judge if a positive urine ELISA test among babies is due to a new filarial infection.

An enzyme-linked immunosorbent assay (ELISA) to detect filaria-specific urinary IgG4 was tested in samples from 203 children less than five years old and their parents (165 mothers and 127 fathers) in Sri Lanka. There were four IgG4-positive children within 58 days after birth, suggesting the transfer of the antibody from mothers. No positive children were found between days 65 and 417. After day 1,000, the number of the positive individuals and the level of IgG4 increased quickly. The children of urinary IgG4-positive parents showed a higher IgG4 positive rate than those of negative parents. The children of positive mothers had a higher prevalence than those of negative mothers, whereas, the positivity of the fathers was not associated with that of their children. Collecting urine samples was easy to perform and well accepted because of its non-invasiveness. The ELISA will be useful for monitoring filarial infections in very young children, who are a sentinel population for evaluating the intensity of filariasis transmission and effectiveness of control measures.

In Sri Lanka 2741 people from Matara, an endemic area for Wuchereria bancrofti, were examined in 1996/97 for microfilariae by 60-microL blood smear and for circulating filarial antigens by Og4C3 ELISA using filter paper-absorbed whole blood. The overall prevalence of microfilaraemia was 3.4%, and that of antigenaemia 14.4%. The prevalence of antigen-positive and microfilaria-negative people was 11.3%. Analysed by age-group, antigenaemia prevalence was similar in all groups, and the average number of antigen units was already very high in the age-group < 10 years, indicating that the infection started in early childhood. Among those who were antigen positive, the microfilaria prevalence was lower in females than in males. Diethylcarbamazine treatment eliminated microfilariae in 78% of the positives. However, 17 months after the treatment, antigenaemia was still positive in 76% of those who were parasitologically cured.

The Og4C3 enzyme-linked immunosorbent assay (ELISA) to detect circulating Wuchereria bancrofti antigen uses 50 microL of serum. In this study, a whole blood sample absorbed on filter paper was tested as a substitute for serum. Serum samples were obtained from 60 Sri Lankan subjects by venepuncture and finger-prick blood samples from the same individuals were directly absorbed on filter paper. Og4C3 ELISAs using serum and filter paper blood were compared. Despite the fact that the estimated amount of serum available for the ELISA with filter paper blood was only one-fifth of that available when serum was used, the 2 ELISAs gave almost identical results. Of the 39 positive serum samples, 38 were detected using filter paper blood. Employing the ELISA using filter paper blood, 619 people in Matara, Sri Lanka, were examined for antigenaemia. The positivity rate was 22.5%, 3.1 times higher than the rate of microfilaraemia detected by examination of 60 microL blood films.