For trachoma elimination purposes, WHO defines a district as the normal administrative unit for health care management [which] for purposes of clarification consists of a population between 100,000C250,000 persons20. Dipraglurant by repeated ocular infection with the bacterium antibody responses is appropriate for assessing trends in transmission at population level over time. This may be particularly apposite for trachoma, for which host immune responses to repeated ocular infections are critical for development of pathology10C13. One important question is an appropriate threshold of seropositivity to trigger-decision-making by trachoma programs. Preliminary models from multi-country serological data analyses suggest that a mean seroprevalence less than 6.2% and a seroconversion rate (SCR) of below 1.5 per 100 individuals per year in 1C9-year-olds correspond to TF?5%6. However, Dipraglurant more data are needed to evaluate the relationship between overall seroprevalence, SCR and TF prevalence in settings at various stages of the elimination process. Another important consideration for serosurveillance studies is the choice of test to measure anti-antibodies. Because of the discordance between the longevity of infection and antibody positivity, there is no gold standard for antibody testsi.e., a test that can tell who has been exposed sufficiently to generate an antibody response. Antibodies against Pgp3 were first identified by ELISA14, and subsequently have undergone various revisions15C17. We previously adapted testing for anti-Pgp3 antibodies to a multiplex bead assay (MBA), in order to allow evaluation of antibody tests in trachoma-endemic settings Dipraglurant within a multiplexed, integrated, serological surveillance platform3. This was later modified to an ELISA with a series of plate control standards to normalize absorbance values and thereby standardize testing between laboratories15. The test was also adapted to a lateral flow assay (LFA) to provide a rapid, low-cost, low-technical capacity alternative to ELISAs or MBA18,19. As tests are trialed in an increasing variety of epidemiological settings, it is important Dipraglurant to use the data and user feedback to undertake further test optimization, and ultimately work towards rationalizing the menu of options available while consensus emerges on the target product profile. Here, we compare seroconversion rate (SCR) and seroprevalence estimates from four evaluation Dipraglurant units in two countries undergoing baseline mapping for trachoma (Togo and Democratic Republic of the Congo [DRC]) using multiple versions of the LFA and the MBA, including an improved version of the LFA that employs black latex as the developing reagent. Methods Ethics Ethical approval for individual studies was given by institutional review boards at the Togo Ministry of Health and Social Protection and the Ethics Committee of the Ministry of Public Health of the Democratic Republic of the Congo. Written informed consent from parents was obtained for study participants, all of whom Rabbit Polyclonal to BTK (phospho-Tyr223) were aged?18?years. Tropical Data has ethics approval from the London School of Hygiene & Tropical Medicine to support health ministries to conduct trachoma prevalence surveys. CDC staff did not interact with study participants or have access to identifying information and were considered to be non-engaged in research. All methods were carried out in accordance with relevant guidelines and regulations. Study sites In general, an evaluation unit (EU) is a district. For trachoma elimination purposes, WHO defines a district as the normal administrative unit for health care management [which] for purposes of clarification consists of a population between 100,000C250,000 persons20. In Togo, baseline mapping was conducted in seven districts in AugustCSeptember 2017 to determine possible needs for intervention; in 2 of those districts, fingerprick blood was collected to create dried blood spots (DBS) and conduct field testing of the Pgp3 lateral flow assay. In DRC, DBS were collected in June 2018 as part of baseline mapping in 2 health zones of Tanganyika Province. The underlying surveys were conducted in accordance with WHO recommendations for trachoma prevalence surveys21 with.
For trachoma elimination purposes, WHO defines a district as the normal administrative unit for health care management [which] for purposes of clarification consists of a population between 100,000C250,000 persons20
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