# Characterization of arbovirus infections in patients within Haiti by screening discarded malaria rapid diagnostic test cassettes

## TL;DR

This study shows how used malaria test strips in Haiti can detect dengue virus, helping monitor diseases during political instability.

## Contribution

The study demonstrates the repurposing of discarded malaria RDTs for arbovirus surveillance in resource-limited settings.

## Key findings

- Dengue virus serotype 3 was detected in 68 samples collected in 2023.
- No alphavirus or Oropouche virus infections were found in tested samples.
- Sequencing showed high similarity to Caribbean dengue strains from 2022–2023.

## Abstract

Arboviruses represent a diverse group of pathogens transmitted by arthropod vectors. Within Haiti, arboviruses responsible for previous outbreaks include dengue virus, Zika virus, and chikungunya virus. Recent security concerns within Haiti have interrupted broader surveillance efforts, creating challenges for public health agencies tasked with monitoring for vector-borne diseases. In this study, we aimed to better understand circulating arboviruses within Haiti using nucleic acids stored in discarded malaria rapid diagnostic tests (RDTs).

RDTs were collected between 2021–2023 from febrile patients presenting to health care centers throughout the Sud and Ouest Departments of Haiti. Test strips were removed from the RDT cassettes, and total nucleic acid was extracted. Samples were initially tested for sample integrity using a human RNase P real-time PCR assay, followed by a flavivirus spp. real-time PCR assay. A total of 52 RDTs tested positive by the flavivirus spp. assay, and an additional 21 were indeterminant. Testing all flavivirus spp. positive and indeterminant samples with a DENV quadraplex assay resulted in 68 samples testing positive for DENV-3. All samples testing positive for DENV-3 were collected in 2023. NGS sequencing and subsequent phylogenetic analysis demonstrated high sequence similarity to sequences published from the Caribbean region between 2022–2023. A subset of the flavivirus negative RDTs were tested using alphavirus spp. (n = 517) and Oropouche virus (n = 293) real-time RT-PCR assays. No samples tested positive using either the alphavirus spp. (0/517) or Oropouche virus (0/293) assays.

These results demonstrate the context-specific utility of discarded malaria RDTs for remote arbovirus surveillance among febrile patients, with potential for viral characterization. The exclusive finding of DENV-3 within these samples is concordant with the DENV-3 outbreak that was observed throughout the Americas in 2023. As political insecurity continues within Haiti, malarial RDTs represent an important tool for high level surveillance of novel public health threats.

Public health activities such as vector-borne disease surveillance are largely interrupted within countries experiencing humanitarian crises. Within Haiti, a country currently experiencing ongoing political instability, numerous vector-borne viruses (arboviruses) with significant impacts to population health have been detected. Such scenarios necessitate new methods for continued disease surveillance to detect and respond to emerging public health threats. In this study, we demonstrated the repurposed utility of rapid diagnostic tests (RDTs), used in-country for malaria diagnosis among febrile illness patients, for molecular-based surveillance of circulating arboviruses. By extracting genetic material present in the patient blood sample stored within the RDT strip, we detected dengue virus serotype 3 and genetically characterize multiple samples with sequencing. This study presents an extended utility of RDTs for remote molecular-based surveillance of infectious diseases. While this approach requires both coordination with local health care systems to collect anonymized RDTs and access to appropriate biosafety infrastructure for sample processing, such methodology can be used to enhance disease surveillance in other countries undergoing similar crises or in locations where circulating infectious disease profiles have been largely uncharacterized due to logistics-related lack of surveillance capacity.