Vertical Transmission Of Dengue Virus Research Articles

Analysis of clinical characteristics of the 12 cases of neonatal dengue fever in Guangzhou in 2014 and literatures review

To explore the clinical manifestations and laboratory examination characteristics of neonatal dengue fever. A retrospective analysis of 12 cases of neonatal dengue fever treated in the Guangdong Women and Children's Hospital and Guangzhou Women and Children's Medical Center was conducted, and related literature was reviewed. Twelve cases of neonatal dengue fever included 9 males and 3 females; their age was 30 min after birth to 29 d, the age of onset was 30 min-24 d. (1) CLINICAL FEATURES: fever was present in 11 cases, rash in 6 cases, bleeding in 1 case, jaundice in 5 cases, cough in 1 case, coagulopathy in 2 cases. (2) Mothers' perinatal conditions: 7 mothers were confirmed to have dengue fever, 2 mothers had suspected dengue fever, and in 3 mothers the dengue fever was excluded. Eight mothers prenatally had fever. (3) LABORATORY TESTS: Thrombocytopenia was found in 11 cases (19×10(9)-156×10(9)/L), activated partial thromboplastin time prolonged in 11 cases (44.0-89.8 s), fibrinogen decreased in 5 cases (1.17-3.02 g/L), aspartate aminotransferase (AST) increased in 5 cases (28-78 U/L), creatine kinase (CK-MB) increased in 4 cases (13-86 U/L), hypokalemia in 1 case (2.8-5.1 mmol/L ), C- reactive protein (CRP) increased in 6 cases (0.04-46.05 mg/L). (4) Treatment and prognosis: platelet transfusion was used in 2 cases, anti-infective therapy was given to 6 cases, intravenous gamma globulin treatment was used in 5 cases, hospitalization was 4-17 d, 10 cases were cured, 2 cases were discharged after condition was improved. Literature search was performed with "neonatal dengue" as keywords at Wanfang, Weipu, and CNKI, no relevant reports were found. Pubmed search was done with "neonatal dengue" and "case report" as keywords, 15 reports were retrieved during 1990 and 2014, which reported 30 cases, all acquired the disease via vertical transmission; the main clinical manifestations were fever, rash, petechiae, anemia, jaundice, tachycardia, and hepatomegaly; laboratory test: all had visible purpura due to thrombocytopenia; anti-infective treatment, platelet transfusion and symptomatic treatment were given, and all the 30 cases of infants were cured. The clinical manifestations of neonatal dengue fever are characterized by fever and the disorder of blood coagulation system. The course of disease is mild, lack of specific clinical symptoms, and the prognosis is good. Mother to infant vertical transmission of dengue virus is one of the ways of transmission.

Natural vertical transmission of dengue viruses in Aedes aegypti in selected sites in Cebu City, Philippines.

We attempted to determine the vertical transmission of dengue virus (DENV) in Aedes aegypti in selected sites in Cebu City, Philippines. Mosquito sub-adults were collected monthly from households and the field during the wet-dry-wet season from November, 2011 to July, 2012 and were laboratory-reared to adults. Viral RNA extracts in mosquitoes were assayed by hemi-nested RT-PCR. Results showed that 62 (36.26%; n=679) out of 171 mosquito pools (n=2,871) were DENV+. The minimum infection rate (MIR) of DENV ranged from 0 in wet months to 48.22/1,000 mosquitoes in April, 2012 (mid-dry). DENVs were detected in larvae, pupae, and male and female adults, with DENV-4, DENV-3, and DENV-1, in that rank of prevalence. DENV-1 co-infected with either DENV-3 or -4 or with both in April, 2012; DENV-3 and -4 were present in both seasons. More DENV+ mosquitoes were collected from households than in field premises (p<0.001) and in the dry than in the wet season (p<0.05), with significant interaction (p<0.05) between sites and premises but no interaction between sites and seasons (p>0.05). By Generalized Linear Mixed models, the type of premises nested in sites and monthly total rainfall were significant predictors of monthly dengue cases (p<0.05) and not MIR, season, temperature, and relative humidity. Surveillance of DENV prevalence in Ae. aegypti and detecting their natural foci in the dry season provide an early warning signal of dengue outbreak.

How Important is Vertical Transmission of Dengue Viruses by Mosquitoes (Diptera: Culicidae)?

Vertical transmission of dengue viruses by mosquitoes was discovered at the end of the late 1970s and has been suggested to be a means by which these viruses persist. However, it is unclear how widespread it is in nature, and its importance in the epidemiology of this disease is still debated. Here, we review the literature on vertical transmission and discuss its role in dengue's epidemiology and control. We conclude that given the number of studies that failed to find evidence of vertical transmission, as well as mathematical models and its mechanistic basis, it is unlikely that vertical transmission is important for the epidemiological persistence of dengue viruses. A combination of asymptomatic infection in humans and movement of people are likely to be more important determinants of dengue's persistence. We argue, however, that there may be some need for further research into the prevalence of dengue viruses in desiccated, as well as diapausing, eggs and the role of horizontal transmission through larval cannibalism.

Breast Milk as a Possible Route of Vertical Transmission of Dengue Virus?

We report a case of vertical transmission of dengue infection. The virus was detected and quantified by reverse-transcription polymerase chain reaction in sequential blood samples from mother and child as well as in breast milk, but not in cord blood. This case poses questions about the risk of breastfeeding transmission of dengue virus.

Vertical Transmission of Dengue Virus in Aedes aegypti Collected in Surabaya, Indonesia, during 2008^|^ndash;2011

*Corresponding author: Present address: CRC-ERID, Institute of Tropical Disease, Airlangga University, Kampus C, UNAIR, Jl. Mulyorejo, Surabaya 60115, Indonesia. E-mail: paradios99@yahoo.co.jp **Endowed from The Research Foundation for Microbial Diseases of Osaka University, Osaka, Japan to Research Institute for Microbial Diseases, Osaka University, Osaka, Japan. Jpn. J. Infect. Dis., 65, 274-276, 2012

Perinatal Transmission of Yellow Fever, Brazil

Perinatal Transmission of Yellow Fever, Brazil

Natural vertical transmission of dengue viruses byAedes aegyptiin Bolivia

The natural transmission of dengue virus from an infected female mosquito to its progeny, namely the vertical transmission, was researched in wild caught Aedes aegypti during an important outbreak in the town of Santa Cruz de la Sierra, Bolivia. Mosquitoes were collected at the preimaginal stages (eggs, larvae and pupae) then reared up to adult stage for viral detection using molecular methods. Dengue virus serotypes 1 and 3 were found to be co-circulating with significant higher prevalence in male than in female mosquitoes. Of the 97 pools of Ae. aegypti (n = 635 male and 748 female specimens) screened, 14 pools, collected in February-May in 2007, were found positive for dengue virus infection: five DEN-1 and nine DEN-3. The average true infection rate (TIR) and minimum infection rate (MIR) were respectively 1.08% and 1.01%. These observations suggest that vertical transmission of dengue virus may be detected in vectors at the peak of an outbreak as well as several months before an epidemic occurs in human population.

Dengue in infants: an overview

Dengue virus (DV) infection causes either a benign syndrome, dengue fever, or a severe syndrome, dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS), that is characterized by systemic capillary leakage, thrombocytopaenia and hypovolaemic shock. DHF/DSS occur mainly due to secondary infection by a heterotype DV infection in children and adults but in infants even primary infection by DV causes DHF/DSS. Clinical manifestations of DHF/DSS are more significantly associated with death in infants compared with older children. Vertical transmission of DV and anti-DV IgG has been well reported and is responsible for the pathogenesis of DV disease and its manifestations in infants. The complex pathogenesis of DHF/DSS during primary dengue in infants, with multiple age-related confounding factors, offers unique challenges to investigators. Dengue in infants is not often studied in detail due to practical limitations, but looking at the magnitude of DHF/DSS in infants and the unique opportunities this model provides, there is a need to focus on this problem. This paper reviews existing knowledge on this aspect of DV infection and the challenges it provides.

Evidence of Vertical Transmission of Dengue Virus in Two Endemic Localities in the State of Oaxaca, Mexico

Background: Dengue virus is spread in tropical areas of the world and is the causative agent of dengue fever and dengue hemorrhagic fever. It is horizontally transmitted to humans by infected Aedes mosquitoes, but it is also able to be vertically or transovarially transmitted to insect progeny. Objective: In this work, we analyzed the vertical transmission of dengue virus in Aedes aegypti mosquitoes collected in two endemic localities in the state of Oaxaca, Mexico. Methods: The collected larvae were grown in the laboratory and transovarial transmission of dengue virus, either in larvae or newly emerged mosquitoes, was investigated using a semi-nested reverse transcription-polymerase chain reaction method. Results: Although the presence of dengue virus in larvae could not be demonstrated, the viral genome was amplified in 4 out of 43 pools of in-cage born mosquitoes: DEN 2, 3 and 4 serotypes were detected in 2 pools from Tuxtepec and two from Juchitán. Conclusion: The results presented here strongly suggest that dengue virus can be vertically transmitted in mosquitoes from Oaxaca, but more studies will be necessary to analyze the epidemiological impact of this mechanism of transmission.

Natural vertical transmission of dengue viruses in Aedes aegypt in southern India

Natural vertical transmission of dengue viruses in Aedes aegypt in southern India

Determination of dengue virus serotypes in individual Aedes aegypti mosquitoes in Colombia.

Adult Aedes aegypti mosquitoes were collected in Puerto Triunfo, central Colombia, where dengue is endemic, during a six month period. Viral infection within the head of each individual mosquito was identified by an immunofluorescent assay (IFA) using a flavivirus-specific monoclonal antibody. The dengue virus serotype, present in each flavivirus-positive specimen, was then determined in portions of the remaining thorax using IFAs with serotype-specific monoclonal antibodies. Among 2065 female Aedes aegypti collected and tested, twenty-four flavivirus-positive individuals were found (minimum infection rate 11.6%), three identified as dengue type-1 and twenty-one as dengue type-2 virus. This was consistent with the isolation of only these two serotypes of dengue virus from dengue fever patients within this town. No vertical transmission of dengue virus could be detected in 1552 male Aedes aegypti collected. This method is inexpensive, simple, rapid to perform and suitable for use in developing countries to identify and distinguish different serotypes of dengue virus in their vectors during eco-epidemiological investigations.

Vertical Transmission of Dengue

Dengue, an important mosquito-borne flavivirus infection, is endemic in Southeast Asia. We describe two mothers who had acute dengue 4 and 8 days before the births of their infants. One mother had worsening of her proteinuric pregnancy-induced hypertension, liver dysfunction, and coagulopathy and required multiple transfusions of whole blood, platelets, and fresh frozen plasma. Her male infant was ill at birth, developed respiratory distress and a large uncontrollable left intracerebral hemorrhage, and died of multiorgan failure on day 6 of life. Dengue virus type 2 was isolated from the infant's blood, and IgM antibody specific to dengue virus was detected in the mother's blood. The second mother had a milder clinical course; she gave birth to a female infant who was thrombocytopenic at birth and had an uneventful hospitalization. Dengue virus type 2 was recovered from the mother's blood, and IgM antibody specific to dengue virus was detected in the infant's blood. This report highlights not only the apparently rare occurrence of vertical transmission of dengue virus in humans but also the potential risk of death for infected neonates.

Vertical transmission of dengue viruses by mosquitoes of the Aedes scutellaris group.

Seventeen strains of mosquitoes belonging to 12 species in the Aedes scutellaris subgroup were tested for an ability to transmit one or more dengue virus serotype(s) vertically. Strains of virus employed for dengue types 1, 2, 3, and 4 were from Fiji, Bangkok, Burma, and Medan, respectively. After parental females were infected by intrathoracic inoculation, F1 larval and pupal progeny were tested for the presence of virus by inoculating aliquots of triturated suspensions into Toxorhynchites amboinensis mosquitoes. Dengue type 1 was transmitted vertically by 11 strains of mosquitoes representing 8 species with the highest filial infection rates observed for Ae. cooki (1.2%). Vertical transmission of the other dengue virus serotypes was observed for fewer species of mosquitoes, however the filial infection rates of those demonstrating vertical transmission were between 1%-2% for types 2 and 3, and about 0.5% for type 4. Tests with the progeny of individual Ae. cooki and Ae. polynesiensis infected with dengue virus types 1 and 3, respectively, showed that approximately greater than or equal to 50% of the parental females transmitted virus to their progeny. Highest filial infection rates were 6.7% for Ae. cooki and 4.6% for Ae. polynesiensis.