Cost-Effective Method Detects Chikungunya virus

Venous blood samples can be difficult to obtain for the diagnosis of CHIKV and the shipment of serum in appropriate temperature conditions is too costly for most developing countries.

Scientists at the Institut Pasteur de Madagascar (Antananarivo, Madagascar) collected samples from all patients, visiting sentinel centers, that fulfilled the case definition for dengue-like illness with onset within the previous five days were included in the study. Both venous blood and capillary blood were collected and spotted onto a clean Whatman 3MM filter paper (Sigma-Aldrich; St. Louis, MO, USA).

All samples were tested by real-time polymerase chain reaction (RT-PCR) and results with serum and dried-blood blotted on filter paper (DBFP) samples were compared for each patient. CHIKV ribonucleic acid (RNA) was detected by one-step real-time RT-PCR assays in a Rotorgene 6000 apparatus (Corbett Life Science; Mortlake, NSW, Australia; www.corbettlifescience.com).


Overall, 181 samples from patients presenting dengue-like illness were included in the study: 73 (40.3%) were CHIKV confirmed cases and 108 (59.7%) were negative controls; the median age was 18 years and 32 years, and sex ratio (M/F) were 1.2 and 0.5, respectively. Among the 181 patients tested, DBFP for 74 (40.9%) and sera for 73 (40.3%) scored positive for CHIKV. The sensitivity and specificity of tests performed with DBFP were very similar to those with venous samples. The loss of sensitivity was insignificant and involved a very small number of patients, all with low viral loads.

The authors concluded that DBFP is a cost-effective method for surveillance and for the monitoring of viral outbreaks in low-income countries, and especially in large countries where the access to laboratory facilities is limited. This method can facilitate the extension of surveillance system networks, and may be useful to public health authorities for rapid identification of Chikungunya outbreaks and, by extension, those of other arboviruses, such as Dengue fever, Rift Valley Fever, West Nile. The study was published on July 25, 2013, in the journal Public Library of Science Neglected Tropical Diseases.

Related Links:

Institut Pasteur de Madagascar
Sigma-Aldrich
Corbett life science