ABSTRACT
Dengue virus (DENV) is one of the most important mosquito-borne diseases. It belongs to the genus Flavivirus of the family Flaviviridae and is a small enveloped, positive single-stranded RNA virus. Dengue virus comprise four distinct serotypes, DEN-1 through DEN-4, which are transmitted from infected to healthy humans through bites of female Aedes aegypti and A. albopictus. Dengue infection is a major cause of morbidity and mortality in tropical and subtropical countries. Over 2.5 billion people are at risk of dengue infection, and about 100 million cases of dengue fever occur annually. Up to 500,000 of these develop dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), the life-threatening forms of infection. At present, no proven vaccine is available for all 4 dengue serotypes, nor specific antiviral drugs to treat infection. Studies of the viral structure, clinical presentation and classification, basic to advanced diagnostic tools, and primary treatments, are necessary for effective disease prevention and control. This review summarizes current basic knowledge of dengue virus infection, based on clinical and laboratory studies. This overview of dengue virus infection should be useful for developing disease control programs and further research.
ABSTRACT
The peritrophic membrane (PM) is an acellular sheath that lines the digestive tract, separating the ingested food bolus from the midgut epithelium. It plays important roles in protecting the midgut epithelium from mechanical damage and insults from pathogens, and in facilitating food digestion. The purpose of this study was to examine the involvement of the PM in the midgut of Aedes aegypti mosquitoes after blood feeding. Ae. aegypti mosquitoes were fed with sucrose and blood, and collected at 0.5, 1, and 6 h post-oral feeding, respectively. Then, they were fixed in 2.5% glutaraldehyde in 0.1 M cacodylate buffer containing 5% sucrose pH 7.4 at 4°C, and prepared for study under a light microscope.PM was not produced when the mosquitoes received sucrose or fasted. Contrary to the blood feeding group, the PM clearly formed at 6 h post-feeding. It was concluded that PM construction was related to the ingestion of blood by the mosquitoes.
ABSTRACT
We conducted a study to compare the safety and tolerability of anti-relapse drugs elubaquine and primaquine against Plasmodium vivax malaria. After standard therapy with chloroquine, 30 mg/kg given over 3 days, 141 patients with P. vivax infection were randomized to receive primaquine or elubaquine. The 2 treatment regimens were primaquine 30 mg once daily for 7 days (group A, n = 71), and elubaquine 25 mg once daily for 7 days (group B, n = 70). All patients cleared parasitemia within 7 days after chloroquine treatment. Among patients treated with primaquine, one patient relapsed on day 26; no relapse occurred with elubaquine treatement. Both drugs were well tolerated. Adverse effects occurred only in patients with G6PD deficiency who were treated with primaquine (group A, n = 4), whose mean hematocrit fell significantly on days 7, 8 and 9 (P = 0.015, 0.027, and 0.048, respectively). No significant change in hematocrit was observed in patients with G6PD deficiency who were treated with elubaquine (group B, n = 3) or in patients with normal G6PD. In conclusion, elubaquine, as anti-relapse therapy for P. vivax malaria, was as safe and well tolerated as primaquine and did not cause clinically significant hemolysis.