Defining the cost of the Egyptian lymphatic filariasis elimination programme

BACKGROUND: Lymphatic filariasis (LF) is targeted for global elimination. LF elimination programmes in different countries, including Egypt, are supported financially by national and international agencies. The national programme in Egypt is based on mass drug administration (MDA) of an annual dose of a combination of 2 drugs (DEC and albendazole) to all endemic villages. This study aimed primarily to estimate the Total and Government costs of two rounds of MDA conducted in Egypt in 2000 and 2001, the average cost per person treated, and the cost share of the different programme partners. METHODS: The Total costs reflect the overall annual costs of the MDA programme, and we defined Government costs as those expenditures made by the Egyptian government to develop, implement and sustain the MDA programmes. We used a generic protocol developed in coordination with the Emory Lymphatic Filariasis Support Center. Our study was concerned with all costs to the government, donors and other implementing parties. Cost data were retrospectively gathered from local, regional and national Ministry of Health and Population records. The total estimates for each governorate were based on data from a representative district for the governorate; these were combined with national programme data for a national estimate. RESULTS: The overall Total and Government costs for treating approximately 1,795,553 individuals living in all endemic villages in the year 2000 were US $3,181,000 and US$2,412,000, respectively. In 2001, the number of persons treated increased (29%) and the Total costs were US $3,109,000 while Government costs were US$2,331,000. In 2000, the average Total and Government costs per treated subject were US $1.77 and$1.34, respectively, however, these costs decreased to US $1.34 and$1.00, respectively in 2001. The coverage rate was 86.0% in 2000 and it increased to 88.0% in 2001. CONCLUSION: The Egyptian government provided 75.8% of all resources, as reflected in the Total cost estimates, and international agencies contributed the rest. Such data highlight both the commitment of the Egyptian government and the significance of the contributions of international bodies toward the LF elimination programme

Knowledge and practice related to compliance with mass drug administration during the Egyptian national filariasis elimination program

Lymphatic filariasis (LF) has been targeted for global elimination by 2020. The primary tool for the program is mass drug administration (MDA) with antifilarial medications to reduce the source of microfilariae required for mosquito transmission of the parasite. This strategy requires high MDA compliance rates. Egypt initiated a national filariasis elimination program in 2000 that targeted approximately 2.7 million persons in 181 disease-endemic localities. This study assessed factors associated with MDA compliance in year three of the Egyptian LF elimination program. 2,859 subjects were interviewed in six villages. The surveyed compliance rate for MDA in these villages was 85.3% (95% confidence interval = 83.9–86.5%). Compliance with MDA was positively associated with LF knowledge scores, male sex, and older age. Adverse events reported by 18.4% of participants were mild and more common in females. This study has provided new information on factors associated with MDA compliance during Egypt's successful LF elimination program

A critical appraisal of molecular xenomonitoring as a tool for assessing progress toward elimination of lymphatic filariasis

We used molecular xenomonitoring (MX, detection of filarial DNA in mosquitoes) to evaluate the impact of mass drug administration (MDA) in sentinel locations in Egypt with high (11.5%) and low (4.1%) baseline microfilaria prevalence rates. Blood-fed Culex pipiens were pooled by household and tested for Wuchereria bancrofti DNA by PCR. There was no significant relationship between the infection status of household residents and parasite DNA status of mosquitoes from the same houses. After 5 MDA rounds, parasite DNA rates in mosquitoes in high- and low-prevalence areas were reduced by 93.8% and 100% to 0.19% (95% CI: 0.076–0.382%) and 0% (95% CI: 0–0.045%), respectively. These changes were consistent with decreases in microfilaria prevalence rates in these sites; they provide insight regarding the minimal mosquito DNA rates necessary for sustained transmission of filariasis in Egypt. We conclude that MX is a powerful tool for monitoring the impact of MDA on filariasis endemicity and transmission

A Reverse Transcriptase-PCR Assay for Detecting Filarial Infective Larvae in Mosquitoes

Background: Existing molecular assays for filarial parasite DNA in mosquitoes cannot distinguish between infected mosquitoes that contain any stage of the parasite and infective mosquitoes that harbor third stage larvae (L3) capable of establishing new infections in humans. We now report development of a molecular L3-detection assay for Brugia malayi in vectors based on RT-PCR detection of an L3-activated gene transcript. Methodology/Principal Findings: Candidate genes identified by bioinformatics analysis of EST datasets across the B. malayilife cycle were initially screened by PCR using cDNA libraries as templates. Stage-specificity was confirmed using RNA isolated from infected mosquitoes. Mosquitoes were collected daily for 14 days after feeding on microfilaremic cat blood. RT-PCR was performed with primer sets that were specific for individual candidate genes. Many promising candidates with strong expression in the L3 stage were excluded because of low-level transcription in less mature larvae. One transcript (TC8100, which encodes a particular form of collagen) was only detected in mosquitoes that contained L3 larvae. This assay detects a single L3 in a pool of 25 mosquitoes. Conclusions/Significance: This L3-activated gene transcript, combined with a control transcript (tph-1, accession # U80971) that is constitutively expressed by all vector-stage filarial larvae, can be used to detect filarial infectivity in pools of mosquito vectors. This general approach (detection of stage-specific gene transcripts from eukaryotic pathogens) may also be useful for detecting infective stages of other vector-borne parasites

Detection of Wuchereria bancrofti L3 Larvae in Mosquitoes: A Reverse Transcriptase PCR Assay Evaluating Infection and Infectivity

Lymphatic filariasis is a disabling and disfiguring disease caused by a parasite that is transmitted by a mosquito. The life cycle of the parasite requires two hosts: the mosquito vector and the human host. Part of the developmental life cycle of the parasite occurs in the mosquito and the other part in the human host. The parasite develops through four stages in the mosquito, only the last of which is infectious to humans. The third larval stage (L3) is the infective stage that initiates human infections when infective mosquitoes bite humans. There is currently a global program attempting to eliminate this disease by administering drugs to affected communities with the goal of interrupting transmission of the parasite. The new diagnostic tool described in this paper uses molecular techniques to specifically detect the infective stage of the parasite in mosquitoes. Many mosquitoes can be tested at one time to assess the risk of ongoing transmission of filariasis in communities. In addition, this new L3-detection assay can simultaneously detect whether the mosquitoes contain ‘any-stage’ of the parasite. This provides information on infection rates in humans in the community. Both pieces of information can be used in assessing the progress of disease elimination efforts

The effect of compliance on the impact of mass drug administration for elimination of lymphatic filariasis in Egypt

We studied effects of compliance on the impact of mass drug administration (MDA) with diethylcarbamazine and albendazole for lymphatic filariasis (LF) in an Egyptian village. Baseline microfilaremia (mf) and filarial antigenemia rates were 11.5% and 19.0%, respectively. The MDA compliance rates were excellent (> 85%). However, individual compliance was highly variable; 7.4% of those surveyed after five rounds of MDA denied having ever taken the medications and 52.4% reported that they had taken all five doses. The mf and antigenemia rates were 0.2% and 2.7% in those who reported five doses of MDA and 8.3% and 13.8% in those who reported zero doses. There was no significant difference in residual infection rates among those who had taken two or more doses. These results underscore the importance of compliance for LF elimination programs based on MDA and suggest that two ingested doses of MDA are as effective as five doses for reducing filariasis infection rates

A real-time PCR-based assay for detection of Wuchereria bancrofti DNA in blood and mosquitoes

We developed and evaluated real-time polymerase chain reaction (PCR) assays for detecting Wuchereria bancrofti DNA in human blood and in mosquitoes. An assay based on detection of the W. bancrofti “LDR” repeat DNA sequence was more sensitive than an assay for Wolbachia 16S rDNA. The LDR-based assay was sensitive for detecting microfilarial DNA on dried membrane filters or on filter paper. We also compared real-time PCR with conventional PCR (C-PCR) for detecting W. bancrofti DNA in mosquito samples collected in endemic areas in Egypt and Papua New Guinea. Although the two methods had comparable sensitivity for detecting filarial DNA in reference samples, real-time PCR was more sensitive than C-PCR in practice with field samples. Other advantages of real-time PCR include its high-throughput capacity and decreased risk of cross-contamination between test samples. We believe that real-time PCR has great potential as a tool for monitoring progress in large-scale filariasis elimination programs