Concept: Tamil people
Previous studies that pooled Indian populations from a wide variety of geographical locations, have obtained contradictory conclusions about the processes of the establishment of the Varna caste system and its genetic impact on the origins and demographic histories of Indian populations. To further investigate these questions we took advantage that both Y chromosome and caste designation are paternally inherited, and genotyped 1,680 Y chromosomes representing 12 tribal and 19 non-tribal (caste) endogamous populations from the predominantly Dravidian-speaking Tamil Nadu state in the southernmost part of India. Tribes and castes were both characterized by an overwhelming proportion of putatively Indian autochthonous Y-chromosomal haplogroups (H-M69, F-M89, R1a1-M17, L1-M27, R2-M124, and C5-M356; 81% combined) with a shared genetic heritage dating back to the late Pleistocene (10-30 Kya), suggesting that more recent Holocene migrations from western Eurasia contributed <20% of the male lineages. We found strong evidence for genetic structure, associated primarily with the current mode of subsistence. Coalescence analysis suggested that the social stratification was established 4-6 Kya and there was little admixture during the last 3 Kya, implying a minimal genetic impact of the Varna (caste) system from the historically-documented Brahmin migrations into the area. In contrast, the overall Y-chromosomal patterns, the time depth of population diversifications and the period of differentiation were best explained by the emergence of agricultural technology in South Asia. These results highlight the utility of detailed local genetic studies within India, without prior assumptions about the importance of Varna rank status for population grouping, to obtain new insights into the relative influences of past demographic events for the population structure of the whole of modern India.
Located only a short distance off the southernmost shore of the Greater Indian subcontinent, the island of Sri Lanka has long been inhabited by various ethnic populations. Mainly comprising the Vedda, Sinhalese (Up- and Low-country) and Tamil (Sri Lankan and Indian); their history of settlements on the island and the biological relationships among them have remained obscure. It has been hypothesized that the Vedda was probably the earliest inhabitants of the area, followed by Sinhalese and Tamil from the Indian mainland. This study, in which 271 individuals, representing the Sri Lankan ethnic populations mentioned, were typed for their mitochondrial DNA (mtDNA) hypervariable segment 1 (HVS-1) and part of hypervariable segment 2 (HVS-2), provides implications for their settlement history on the island. From the phylogenetic, principal coordinate and analysis of molecular variance results, the Vedda occupied a position separated from all other ethnic people of the island, who formed relatively close affiliations among themselves, suggesting a separate origin of the former. The haplotypes and analysis of molecular variance revealed that Vedda people’s mitochondrial sequences are more related to the Sinhalese and Sri Lankan Tamils' than the Indian Tamils' sequences. MtDNA haplogroup analysis revealed that several West Eurasian haplogroups as well as Indian-specific mtDNA clades were found amongst the Sri Lankan populations. Through a comparison with the mtDNA HVS-1 and part of HVS-2 of Indian database, both Tamils and Sinhalese clusters were affiliated with Indian subcontinent populations than Vedda people who are believed to be the native population of the island of Sri Lanka.Journal of Human Genetics advance online publication, 7 November 2013; doi:10.1038/jhg.2013.112.
Hemoprotozoan parasites are responsible for significant economic losses in cattle. We screened Sri Lankan cattle populations for the presence of Babesia bovis, Babesia bigemina, Theileria annulata, and Theileria orientalis, using species-specific PCR assays. Out of 316 samples collected from animals in four different districts of Sri Lanka (Nuwara Eliya, Polonnaruwa, Ampara, and Jaffna), 231 (73.1%) were positive for at least one parasite species. All four parasite species were detected among the study groups from all of the districts surveyed. The first and second commonest hemoprotozoan parasites identified were T. orientalis (53.5%) and B. bigemina (30.1%), respectively. We found that the dry zones (Polonnaruwa, Ampara, and Jaffna) had more Babesia-positive animals than the hill country wet zone (Nuwara Eliya). In contrast, T. orientalis was the predominant species detected in Nuwara Eliya, while infection with T. annulata was more common in the dry zones. In addition, 81 (35.1%) of the 231 positive samples were infected with more than one parasite species. The presence of multiple parasite species among the different cattle populations is of clinical and economic significance. Therefore, island-wide control and prevention programs against bovine babesiosis and theileriosis are needed to minimize the financial burden caused by these parasites.
BACKGROUND: India has seen rapid unorganized urbanization in the past few decades. However, the burden of childhood diseases and malnutrition in such populations is difficult to quantify. The morbidity experience of children living in semi-urban slums of a southern Indian city is described. METHODS: A total of 176 children were recruited pre-weaning from four geographically adjacent, semi-urban slums located in the western outskirts of Vellore, Tamil Nadu for a study on water safety and enteric infections and received either bottled or municipal drinking water based on their area of residence. Children were visited weekly at home and had anthropometry measured monthly until their second birthday. RESULTS: A total of 3932 episodes of illness were recorded during the follow-up period, resulting in an incidence of 12.5 illnesses/child-year, with more illness during infancy than in the second year of life. Respiratory, mostly upper respiratory infections, and gastrointestinal illnesses were most common. Approximately one third of children were stunted at 2 years of age, and two-thirds had at least one episode of growth failure during the two years of follow up. No differences in morbidity were seen between children who received bottled and municipal water. CONCLUSIONS: Our study found a high burden of childhood diseases and malnutrition among urban slum dwellers in southern India. Frequent illnesses may adversely impact children’s health and development, besides placing an additional burden on families who need to seek healthcare and find resources to manage illness.
Tuberculosis (TB) is a major global health problem, commonly seen in underdeveloped countries. The probability of contracting the disease is significantly higher among the economically vulnerable and the socially disadvantaged. Risk factors associated with TB can also change over time. In the Sri Lankan context, no study has explored how these factors impact patients. Therefore, we aimed to explore social status, associated risk factors and lifestyle changes during the treatment period of TB patients attending a tertiary respiratory center in Colombo, Sri Lanka.
Preparation and characterization of excretory and secretory antigen ofCotylophoron cotylophorumandGastrothylax crumenifer
- Journal of parasitic diseases : official organ of the Indian Society for Parasitology
- Published almost 2 years ago
Excretory and secretory antigen of adultCotylophoron cotylophorumandGastrothylax crumeniferwas prepared and characterized by SDS-PAGE. Adult paramphistomes were collected in PBS from rumen of sheep slaughtered at Perambur and Villivakkam slaughter houses, Chennai, Tamil Nadu. Excretory/Secretory (E/S) antigens ofG. crumeniferandC. cotylophorumwere prepared by incubating in PBS at 28.3 °C overnight in a shaking incubator and centrifuged. The culture supernatant was used as antigen. The protein concentration of E/S antigens ofC. cotylophorumandG. crumeniferranged from 0.4 to 7.1 mg/ml and 3.3 to 5.9 mg/ml, respectively. SDS-PAGE analysis of E/S antigen ofC. cotylophorumrevealed two polypeptide bands from the range of 32 and 40 kDa. Whereas, SDS-PAGE analysis of E/S antigen ofG. crumeniferrevealed only one polypeptide band of 35 kDa. Excretory/secretory antigen may be used for serodiagnosis of paramphistomosis infection in sheep.
Unlike the bats of New World, Old World bats are not considered to transmit rabies virus (RABV). Two RABV variants are circulating in Sri Lanka; one variant is circulating in dogs and other animals. The other variant has been identified in a wild civet. There is possibility that other variants are also circulating among the wild animals in Sri Lanka. Therefore we performed molecular characterization of the RABVs present in Sri Lankan wild animals. Samples from wild animals, dogs, cats and humans with suspected rabies submitted at the Department of Rabies Diagnosis and Research, Medical Research Institute (MRI), Colombo, Sri Lanka were used in this study. We identified a RABV in a Sri Lankan bat known as Indian flying fox (Pteropus medius). Phylogenetic analysis of the N gene showed that the RABV from the bat formed a separate phylogenetic lineage in the Sri Lankan RABV group. RABVs in this lineage come from wild animals only and possess three nucleotide substitutions compared with others. This result indicates that Old World bats may be infected with RABV and therefore further studies are needed.
A large outbreak of dengue occurred in Tamil Nadu, South India in 2012 with 12,000 cases and CFR of 0.5%. Molecular characterization of virus present in the sera of dengue patients was undertaken to determine if there were changes in the virus population. All four serotypes were circulating but DENV-1 was dominant, present in 52% of the serotyped samples. Furthermore, the genotype of only DENV-1 had changed; the Asian genotype had displaced the American/African. Phylogenetic analysis revealed that the Asian genotype was introduced from Singapore and shared 99% similarity with viruses, associated with large outbreaks in Singapore and Sri Lanka. We report for the first time the emergence of the Asian genotype of DENV-1 in southern India causing an extensive and severe outbreak. The study proves how movement of DENV can affect dengue outbreaks and underscores the need for close molecular monitoring of DENV.
here are unique ethical considerations in conducting international research with war and disaster-affected populations that are important for ensuring adequate protection of participants. Of particular importance is the distress that participants may experience as a result of being asked about traumatic stressors, psychological symptoms, and life problems. In this study, trauma-affected Tamil women in Eastern Sri Lanka were asked to report on their research-participation experience after taking part in a larger study on risk and resiliency. Results indicated that most participants experienced emotional upset as a result of taking part in the study. However, the degree of distress was generally not more than they anticipated, and most participants reported they would have participated had they known in advance how they would feel. Most participants perceived some benefit as a result of participating and agreed that items were personally relevant. Emotional distress from participation positively correlated with culturally specific symptoms of anxiety and depression. Contextual stressors and social support were not associated with participation-related distress. We discuss these findings as well as general issues that might arise in international research with trauma-affected populations. (PsycINFO Database Record
Sri Lanka has been free from indigenous malaria since November 2012 and received the WHO certificate for malaria-free status in September 2016. Due to increased global travel, imported malaria cases continue to be reported in the country. Military personnel returning home from international peace-keeping missions in malaria endemic countries represent a key risk group in terms of imported malaria. The present study intended to characterize the potential causes of a malaria outbreak among the Sri Lankan security forces personnel deployed in the Central African Republic (CAR).