SERS Platform for Dengue Diagnosis from Clinical Samples Employing a Hand Held Raman Spectrometer.

Dengue is a serious global health concern especially in tropical and subtropical countries. About 2.5 billion of the world's population is at risk for dengue infection. Early diagnosis is the key to prevent the deterioration of health of the patient to severe illness. Laboratory diagnosis of dengue is essential for providing appropriate supportive treatment to dengue patients with febrile illness, which is difficult to diagnose clinically. Here, we demonstrate surface enhanced Raman scattering (SERS) based diagnosis of dengue virus in clinical blood samples collected from total of 102 subjects. All of the samples were well characterized by conventional NS1 antigen and IgM antibody ELISA kits. The silver nanorods array fabricated by glancing angle deposition technique were employed as SERS substrates. A small amount of patient blood serum (5 µL) was taken for analysis and the report was prepared within a minute. SERS spectra of pure NS1 protein as well as spiked in serum was also recorded separately. Principal component analysis (PCA) was employed as the statistical tool to differentiate dengue positive, dengue negative, and healthy subjects on the basis of their respective SERS spectra. This method provides a sensitive, rapid, and field deployable diagnosis of dengue at the early stage (within 5 days of the onset of symptoms).

Comparison of three PCR-based assays for the non-invasive diagnosis of malaria: detection of Plasmodium parasites in blood and saliva.

The conventional molecular diagnosis of malaria uses 18S rRNA-based PCR assay employing blood samples. This assay presents limitation in terms of long turnaround time and increased chances of false-positive results. Here, we evaluated one-step singleplex or multiplex PCR assay based on high copy species-specific consensus repeat sequences (CRS) along with standard 18S rRNA nested PCR (18S n-PCR) assay to detect P. falciparum and P. vivax infection using blood and saliva samples from Indian febrile patients. Out of 327 patients, 187 were found to be positive for malaria parasites by microscopic examination of peripheral blood smears. Among these 130 were P. vivax and 57 were P. falciparum cases. The 18S n-PCR assay and CRS PCR assay identified 186 out of 187 cases (99.4 %). Multiplex CRS PCR assay detected Plasmodium in 176 out of 187 cases (94.1 %). Both singleplex and multiplex CRS PCR assay identified 6 mixed infection cases, while 18S n-PCR assay detected 10 mixed infection cases of P. vivax and P. falciparum, which were not recognized by microscopy. Non-invasive Plasmodium detection rate with DNA derived from saliva samples was highest for 18S n-PCR (87.36 %), followed by singleplex CRS (81 %) and multiplex CRS PCR assay (70.5 %). Specificity for P. vivax and P. falciparum detection for all assays was 98.48 % and 100 % respectively. Detection rate for P. vivax in saliva correlated with parasite density for CRS target-based assays. The species-specific CRS PCR, either as a singleplex or multiplex assay, can have an impact on diagnosis and epidemiological studies in malaria.

Sexually transmitted infections in tribal populations of central India.

This community-based cross-sectional study was carried out in 17 tribal villages of the Kundam block of the Jabalpur district of India. Individuals with sexually transmitted disease (STD) syndromes were enumerated and the specimens were collected for the laboratory diagnosis of sexually transmitted infections (STIs). Trichomoniasis, gonorrhoea, bacterial vaginosis and syphilis sero-reactivity were diagnosed by standard microbiological techniques. Chlamydia infection was detected by using polymerase chain reaction (PCR). A definite laboratory diagnosis of STIs could be established in 36.5% individuals. The most common STI in females was trichomoniasis, while in males, gonorrhoea was the most common. The highest proportion of individuals with STIs (39.2%) was in the age group 30-39 years. There is a need to focus on the primary prevention of STIs in the area.

Prevalence of sexually transmitted disease syndromes in tribal population of central India.

BACKGROUND: A syndromic approach has been advocated for identification and management of sexually transmitted diseases (STDs) in countries where diagnostic laboratory tests are not consistently available. A community-based cross-sectional study was conducted to discover the prevalence of STD syndromes in tribal population of central India. METHODS: All married men and women in the age group of 15-49 years from selected villages were enumerated by house-to-house visit. Individuals were interviewed using pre-coded, pre-tested questionnaires about STD syndromes of urethral discharge, vaginal discharge, dysurea, genital ulcer, inguinal swelling, scrotal swelling and lower abdominal pain. RESULTS: Of the 2568 individuals interviewed, 326 (12.7%) had at least one STD syndrome. The prevalence was almost double in women (17.6%) than in men (8.4%). The highest prevalence (16.2%) was observed in the age group 30-34 years followed by 35-39 years (14.7%). The commonest syndrome in women was vaginal discharge (16.0%) while in men the commonest syndrome was dysurea (1.8%). CONCLUSION: The low level of STD syndromes among tribal populations offers an opportunity to prevent a potential epidemic in this disadvantaged community. As no baseline data are available, the findings form the basis for future work in this area.