Epidemiology of dengue in Sri Lanka before and after the emergence of epidemic dengue hemorrhagic fever.

Abstract

Abstract. Before 1989, dengue epidemiology in Sri Lanka was characterized by frequent transmission of all four dengue serotypes but a low incidence of dengue hemorrhagic fever (DHF). After 1989, cases of DHF dramatically increased. Here we present the results of epidemiologic studies conducted in Colombo, Sri Lanka before and after epidemic emergence of DHF in 1989. We compared the proportion of dengue cases among people with fever attending clinics from 1980 to 1984 and in 1997 and 1998 to determine if an increase in dengue transmission was associated with more DHF cases being reported. We also compared the relative distribution of dengue virus serotypes circulating in Colombo before and after the emergence of DHF. We detected no significant differences in dengue as a proportion of fever cases or in serotype distribution between the pre and post-DHF periods. We conclude that an increase in virus transmission or a change in circulating serotypes does not explain the epidemic emergence of DHF in Sri Lanka.

Comparative evaluation of platelet augmentation activity of Carica papaya leaf juice and hydrocortisone in thrombocytopenic rats

“…Average platelet counts of the test and control groups were (6.89)×10 5 /µL and (6.75)×10 5 /µL respectively before the experiment. In the experiment there was no significant difference in the platelet counts during the first 3 days in either group.…”

“…In the experiment there was no significant difference in the platelet counts during the first 3 days in either group. However, platelet counts within the test group started to fall after Day 3 and remarkable thrombocytopenia developed after 7days and the average value was (2.68)×10 5 /µL. From day 11 Carica papaya leaf juice and Hydrocortisone was given in two test groups following cyclophosphamide and platelet counts observed to reach a peak level at Day 14 (7.83)×10 5 /µL in case of following Carica papaya leaf juice, and (4.05)×10 5 /µL in case of following Hydrocortisone.…”

“…However, platelet counts within the test group started to fall after Day 3 and remarkable thrombocytopenia developed after 7days and the average value was (2.68)×10 5 /µL. From day 11 Carica papaya leaf juice and Hydrocortisone was given in two test groups following cyclophosphamide and platelet counts observed to reach a peak level at Day 14 (7.83)×10 5 /µL in case of following Carica papaya leaf juice, and (4.05)×10 5 /µL in case of following Hydrocortisone. The clotting time was determined on day 15 and it was found to be considerably lower (95.5 ± 2.762 sec) in case of Carica papaya leaf juice than (129±3.124 sec) in Hydrocortisone.…”

“…Both haemorrhagic diathesis and circulatory collapse are the fatal complications of the dengue infection. 5,6 Global attempts have been made to develop new treatment strategies to combat these fatal complications of the dengue infection. 7 Steroids are used in the treatment of idiopathic thrombocytopenic purpura to increase the platelet count, which is mediated by auto antibodies.…”

Ecological and immunological determinants of dengue epidemics

“…In particular, Dengue-2 strains originating in southeast Asia appear to be more pathogenic than their American counterparts (22,23). Evidence as to whether ADE or variation in viral virulence, or both, is consistent with the temporal patterns of dengue incidence remains equivocal (24).…”