TruenatTM - micro real-time-polymerase chain reaction for rapid diagnosis of leptospirosis at minimal resource settings

Background & objectives:

The biological spectrum of leptospirosis ranges from acute undifferentiated febrile illness to severe fatal syndrome or a combination of syndromes. Diagnosis on clinical grounds alone is difficult and depends on laboratory support. However, no confirmatory tests are available, which is rapid and can be performed with minimum facilities available. The objectives of this study were to evaluate the diagnostic utility, accuracy and reproducibility of a rapid real time-PCR based method (Truenat™) for early diagnosis of leptospirosis, and its usage in low resource settings.

Methods:

The Truenat™ test was performed using plasma sample collected from confirmed patients and controls. DNA was extracted from plasma samples and the reaction was performed as per the manufacturer’s instructions. Leptospiral isolates were also used to assess the performance using different serovars.

Results:

Evaluation of the Truenat™ test with RT-PCR as the gold standard showed that Truenat™ had a sensitivity of 97.4 per cent and a specificity of 98.6 per cent. The overall agreement with RT-PCR was 98.2 per cent.

Interpretation & conclusions:

Our results showed that the test would be a useful tool for early diagnosis of leptospirosis in settings with minimal facilities and the test results could be obtained within an hour. This indicates that a specific therapy can be instituted during the early phase of the disease even at peripheral healthcare facilities as well during the outbreaks.

Anopheles sundaicus Mosquitoes as Vector for Plasmodium knowlesi, Andaman and Nicobar Islands, India

Using PCR and sequencing, we found Plasmodium knowlesi in the malaria vector Anopheles sundaicus mosquito collected from Katchal Island in the Andaman and Nicobar Islands, India. We cannot rule out natural transmission of this parasite to humans through this mosquito species. An in-depth investigation is needed to prevent disease outbreaks.

Atypical presentation of Hand foot mouth disease (HFMD) caused by enterovirus serotype Coxsackievirus A6, in India

A 27-year-old male presented in the OPD of Naval Hospital in Port Blair, Andaman Islands, India, in 2011 with a history of low-grade fever associated with malaise and a pruritic skin rash. Case 2 – A 17-year-old male student reported to the OPD at Naval Hospital, Kochi Kerala, India, in August 2015. He presented with eruptions on both the palm and soles with a history of high-grade fever for the past 3–4 days. Clinically, both the cases were diagnosed as hand, foot, and mouth disease (HFMD). Both samples were tested against measles virus and varicella-zoster IgM antibodies by enzyme immunoassay and found negative. Stool sample (case 1) and lesion swab (case 2) were processed by enterovirus reverse transcription polymerase chain reaction and phylogenetic analysis, and both were positive for enterovirus human coxsackievirus A6 (CVA6) (untranslated region [UTR]). Phylogenetic analysis also confirmed that both the CVA6 etiology belonged to the genotype F. HFMD in adults often asymptomatic and very few patients get atypical symptoms. Clinical diagnosis is often troublesome to identify HFMD in such cases. An epidemiological surveillance/vigilance is essential to document these atypical cases in near future in developing countries like India.

Emergence of influenza A (H1N1) PDM09 in the remote Islands of India--a molecular approach

BACKGROUND

A disease outbreak of A (H1N1) PDM09 was reported in Andaman and Nicobar islands in 2009 with an attack rate of 33.5% among settler population and 26.3% among the aboriginal Nicobarese tribe. During the ongoing outbreak of A (H1N1) PDM09 disease in different parts of the world, a subject working in Dubai city of Saudi Arabia, came to Port Blair, following which the pandemic triggered for the first time in these Islands.

MATERIALS AND METHODS

During the period August 2009 to January 2011, 30 confirmed cases of Influenza A (H1N1) PDM09 virus infection was detected. To understand the genetic relationship, the NA gene sequences of the viruses were phylogenetically analysed together along with the virus sequence isolated from other parts of the world.

RESULT

Formation of multiple clusters were observed, with the sequences of Andaman Islands, mainland India, Mexico, Saudi Arabia and few other counties clustering together. The sequence analysis data revealed that there was no specific mutation conferring resistance to oseltamivir among the Andaman A (H1N1) PDM09 virus isolates. The result of phylogenetic analysis have also revealed that the A (H1N1) PDM09 virus might have spread in these remote Islands of India via the subject from Saudi Arabia/Dubai.

CONCLUSION

A (H1N1) PDM09 Influenza outbreak have highlighted the need to strengthen the region-specific pandemic preparedness plans and surveillance strategies.