scholarly journals Aedes aegypti abundance, larval indices and risk for dengue virus transmission in Kinondoni district, Tanzania

2022 ◽  
Vol 50 (1) ◽  
Author(s):  
Baraka L. Ngingo ◽  
Leonard E. G. Mboera ◽  
Augustino Chengula ◽  
Ines Machelle ◽  
Mariam R. Makange ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Risk Indicators ◽  
Transmission Risk ◽  
Mosquito Larvae ◽  
Mosquito Vector ◽  
Limited Information ◽  
Rt Pcr ◽  
Vector Surveillance ◽  
Cross Sectional ◽  
Water Holding

Abstract Background Tanzania has experienced periodic dengue outbreaks with increased incidence since 2010. However, there is limited information on vector dynamics and transmission risk in most parts of the country. This study was conducted to determine Aedes mosquito abundance, larval indices and dengue virus infection rate as risk indicators for DENV transmission in Kinondoni district, Dar es Salaam, Tanzania. Methods A cross-sectional study was conducted in three wards of Kinondoni district in Tanzania between December 2019 and January 2020. In each ward, three streets were randomly selected for adult and immature mosquito sampling. The adult mosquitoes were collected using Mosquito Magnet traps, while mosquito larvae and pupae were inspected in water-holding containers in the selected household compounds. The detection of dengue virus (DENV) in female Aedes mosquitoes was done using a one-step reverse transcription–polymerase chain reaction (RT–PCR) method. Results Of the 1416 adult female mosquitoes collected, Ae. aegypti accounted for 16.8% (n = 238). A total of 333 water-holding containers were inspected and 201 (60.4%) had at least an Aedes larvae or pupae. Water-holding containers supporting the breeding of Aedes larvae and pupae included discarded car tires, flowerpots and small and large plastic containers. The overall House Index, Container Index and Breteau Index were 55.1%, 60.4% and 114.2, respectively. None of the 763 female Aedes mosquitoes tested by RT–PCR was found to be infected with DENV. Conclusion The presence and abundance Ae. aegypti mosquitoes and the large proportion of water-holding containers infested with the mosquito larvae and pupae put residents of Kinondoni district at high risk of DENV transmission. Our findings emphasize the need for continuous mosquito vector surveillance and control to prevent the possibility of future DENV outbreaks in Tanzania.

Reverse Transcriptase PCR (Rt-PCR) for Detection of Dengue and Chikungunya Virus of Mosquito Aedes aegypti in Sokaraja

2020 ◽  
Vol 2 (1) ◽  
pp. 56
Author(s):  
Dyah Retno Annisa ◽  
Endang Srimurni Kusmintarsih ◽  
Trisnowati Budi Ambarningrum
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Reverse Transcriptase ◽  
Chikungunya Virus ◽  
Sampling Method ◽  
Molecular Detection ◽  
Transmission Risk ◽  
Virus Infections ◽  
Rt Pcr ◽  
Cross Sectional

dengue fever (DF). Meanwhile, chikungunya virus causes Chikungunya fever (CF). These diseases involve three organisms, namely virus, mosquito Aedes sp., and human. The transmission of dengue and chikungunya virus is related to the population of Ae. aegypti. Banyumas regency is one of the regions with many cases of dengue and chikungnya virus infections, particularly in Purwokerto, Sokaraja, and Cilongok sub-district. Up to this time, there is no medicine and vaccine provided to treat these viruses effectively. Thus, detection of virus inside vector will be effectively performed in order to predict the transmission risk of dengue and chikungunya virus. This research aimed to know the molecular detection of dengue and chikungunya virus on adult Ae.aegypti mosquito in Sokaraja Region, Banyumas Regency. Survey was done by a cross-sectional method in Sokaraja sub-district from May 2019 – March 2019. Furthermore, technical sampling that used was purposive sampling method of adult Ae.aegypti using BG-Sentital Trap, followed by molecular detection of dengue virus using Two-step RT-PCR and chikungunya gene virus using RT-PCR. Molecular detection of DENV and CHIKV of mosquitoes which collected from Sokaraja region showed negative result

scholarly journals Two Cases of Natural Infection of Dengue-2 Virus in Bats in the Colombian Caribbean

2021 ◽  
Vol 6 (1) ◽  
pp. 35
Author(s):  
Alfonso Calderón ◽  
Camilo Guzmán ◽  
Teresa Oviedo-Socarras ◽  
Salim Mattar ◽  
Virginia Rodríguez ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Viral Infections ◽  
Polyclonal Antibodies ◽  
Natural Infection ◽  
Immunohistochemical Analysis ◽  
Positive Control ◽  
Negative Control ◽  
Sodium Pentobarbital ◽  
Rt Pcr ◽  
Cross Sectional

Dengue, a mosquito-borne zoonotic disease, is the most common vector-borne disease in tropical and subtropical areas. In this study, we aim to demonstrate biological evidence of dengue virus infection in bats. A cross-sectional study was carried out in the departments of Cordoba and Sucre, Colombia. A total of 286 bats were captured following the ethical protocols of animal experimentation. The specimens were identified and euthanized using a pharmacological treatment with atropine, acepromazine and sodium pentobarbital. Duplicate samples of brain, heart, lung, spleen, liver, and kidney were collected with one set stored in Trizol and the other stored in 10% buffered formalin for histopathological and immunohistochemical analysis using polyclonal antibodies. Brain samples from lactating mice with an intracranial inoculation of DENV-2 were used as a positive control. As a negative control, lactating mouse brains without inoculation and bats brains negative for RT-PCR were included. Tissue sections from each specimen of bat without conjugate were used as staining control. In a specimen of Carollia perspicillata captured in Ayapel (Cordoba) and Phylostomus discolor captured in San Carlos (Cordoba), dengue virus was detected, and sequences were matched to DENV serotype 2. In bats RT-PCR positive for dengue, lesions compatible with viral infections, and the presence of antigens in tissues were observed. Molecular findings, pathological lesions, and detection of antigens in tissues could demonstrate viral DENV-2 replication and may correspond to natural infection in bats. Additional studies are needed to elucidate the exact role of these species in dengue epidemics.

scholarly journals Availability and Breeding Preferences of Aedes Mosquitoes in Fifteen High Altitude Localities, Maekel Region, Eritrea: A Cross-sectional Study

2020 ◽  
Author(s):  
Kibreab Tesfamicael Haile ◽  
Meron Berhe Tsegai ◽  
Feven Negusse Sielu ◽  
Liya Tekle Weldu ◽  
Tesfit Brhane Nesserab ◽  
...  
Keyword(s):  
High Altitude ◽  
Dengue Fever ◽  
Cross Sectional Study ◽  
Transmission Risk ◽  
Sectional Study ◽  
Cross Sectional ◽  
Aedes Mosquitoes ◽  
Preventive Actions ◽  
Infestation Indices ◽  
Water Holding

Abstract Background: Even-though dengue fever suspicion started to surface in the high altitude localities of Zoba Maekel, presence of the vector has not been studied. Therefore, the study aimed to identify the availability of Aedes mosquitoes, their breeding preferences, and level of infestation in fifteen localities of this region.Methods: Inspection of all water holding containers, in 740 systematically selected households of fifteen localities, was done identifying immature stages of Aedes mosquitoes. All immatures were then, classified, reared and identified using taxonomic keys. Breeding preferences ratio and infestation indices were calculated.Results: In this study Aedes Aegypti mosquito was found in four localities, whereas mosquito of other Aedes specie was identified in twelve localities. Out of all the households inspected 51 were positive for Aedes immature. All indoor containers studied were free of Aedes infestation, whilst 53 of 874 outdoor containers were infested by Aedes larvae and pupae. In this study, discarded tyres were found to have the highest breeding preference ratio (2.11) and pupal productivity (40%). Plastic barrels had the highest positivity (42%) and were the second most productive type of container (28%). The Household, Container and Breteau Indices of more than half of the localities were higher than the high transmission risk thresholds.Conclusion: The study indicated possibilities of local dengue fever transmission in the studied areas. Hence, in depth confirmative studies should be considered and strategic preventive actions should be commenced in regard to the most preferred sites such as discarded tyres.

scholarly journals Re-emergence of dengue virus in regional Queensland: 2019 dengue virus outbreak in Rockhampton, Central Queensland, Australia

2021 ◽  
Vol 45 ◽  
Author(s):  
Jacina Walker ◽  
Alyssa Pyke ◽  
Paul Florian ◽  
Fred Moore ◽  
Nicolas Smoll ◽  
...  
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Southeast Asia ◽  
Mosquito Control ◽  
Clinical Symptoms ◽  
Control Measures ◽  
Nucleotide Sequencing ◽  
Mosquito Vector ◽  
Vector Surveillance

Objective(s): To describe an autochthonous dengue virus type 2 (DENV-2) outbreak in Central Queensland from May 2019 and subsequent public health actions. Design and setting: Public health outbreak investigation of locally acquired DENV-2 cases in Rockhampton, Central Queensland. This included laboratory investigations, associated mosquito vector surveillance, and control measures implemented in response to the outbreak. Results: Twenty-one locally-acquired DENV-2 cases were identified during the Rockhampton outbreak (from 23 May to 7 October 2019): 13 laboratory-confirmed and eight probable cases. Clinical symptoms included lethargy (100%); fever (95%); headache (95%); and aches and pains (90%). Inspections of premises demonstrated that <i>Aedes aegypti</i> was present in 9.5% of those investigated which was more than half of the premises identified as containing mosquitoes. Nucleotide sequencing of a DENV-2 isolate recovered from the first confirmed case and DENV-2 RNA from an additional 5 patients indicated a single DENV-2 strain was responsible for the outbreak which was most closely related to DENV-2 strains from Southeast Asia. Conclusions: The 2019 DENV-2 outbreak in Rockhampton, Central Queensland, Australia, likely resulted from the importation of a strain, most closely related to DENV-2 strains from Southeast Asia and is the first reported outbreak in the region specifically implicating DENV-2. Given the presence of <i>Aedes aegypti</i> in Rockhampton, appropriate medical and mosquito avoidance advice; ongoing surveillance; and deployment of mosquito control strategies for the prevention of dengue and other mosquito-borne diseases should be priorities for this region.

First Record of Natural Transovarial Transmission of Dengue Virus in Aedes albopictus from Cuba

2021 ◽  
Author(s):  
Luis Augusto Piedra ◽  
Liss Claudia Martínez ◽  
Armando Ruiz ◽  
Juan Ramón Vázquez ◽  
María Guadalupe Guzmán ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Aedes Albopictus ◽  
Nested Pcr ◽  
First Record ◽  
Transovarial Transmission ◽  
Mosquito Larvae ◽  
Rt Pcr ◽  
First Time

Transovarial transmission (TOT) of dengue virus (DENV) in Aedes spp. is an important mechanism for DENV maintenance in nature and may be important in initiating outbreaks. The objective of this study was to explore the occurrence of TOT in wild Aedes albopictus populations in Cuba. Mosquito larvae were collected in Cotorro municipality, Havana, Cuba, and identified to species. Fifteen pools of Ae. albopictus each containing 30 larvae were processed for DENV detection by using conventional RT-PCR and nested PCR. Four out of 15 pools processed were positive for DENV-3, but no other DENV serotype was detected. This is the first time TOT of DENV detected in Cuban field populations of Ae. albopictus, and this suggests that this species may be an important vector of DENV in Cuba.

Inapparent dengue virus infection among students in Mandalay, Myanmar

2019 ◽  
Author(s):  
Aung Kyaw Kyaw ◽  
Mya Myat Ngwe Tun ◽  
Shine Thura Naing ◽  
Thida ◽  
Thein Thein Htwe ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Clinical Manifestations ◽  
Denv Infection ◽  
Rt Pcr ◽  
Serum Samples ◽  
Cross Sectional ◽  
Denv Serotypes ◽  
Secondary Infections ◽  
Serotype 1 ◽  
History Of

AbstractBackgroundA school- and laboratory-based cross-sectional descriptive study was conducted to find out the burden of inapparent dengue virus (DENV) infection in Mandalay where DENV is endemic and there is circulation of all four DENV serotypes.MethodsA total of 420 students who had no history of fever and visited the hospital within 6 months were recruited from three monastic schools. Serum samples were collected and the DENV genome was checked by conventional one-step RT-PCR and anti-DENV IgM and IgG antibodies were determined. Inapparent dengue (DEN) infection is defined as individuals who were either RT-PCR-positive or anti-DENV IgM-positive with no clinical manifestations or mild symptoms, and which are not linked to a visit to a healthcare provider.ResultsAmong 420 students, 38 students (9.0%, 95% CI, 6.4 to 12.2) were confirmed as recent inapparent DEN infection. The DENV serotype-1 was detected in six students. Thirty-one out of 38 (81.6%) laboratory-confirmed inapparent DEN-infected students had primary infections and seven (18.4%) had secondary infections.ConclusionThis study explored the prevalence of inapparent DEN infection rate in urban monastic schools in Mandalay and showed that the rate of primary infection among inapparent DENV-infected children was high.

scholarly journals ACCURATE DETECTION OF VIRAL SEROTYPE DENGUE HEMORRHAGIC FEVER THROUGH AEDES SP MOSQUITOES USING REVERSE TRANSCRIPTASE POLYMERASE CHAIN REACTION (RT-PCR)

2021 ◽  
Vol 10 (2) ◽  
pp. 148-152
Author(s):  
Erlin Yustin Tatontos ◽  
Fihiruddin Fihiruddin ◽  
Nurul Inayati
Keyword(s):  
Dengue Virus ◽  
Community Health ◽  
Health Center ◽  
Dengue Hemorrhagic Fever ◽  
Community Health Center ◽  
Hemorrhagic Fever ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Vector Mosquito ◽  
Pcr Method

Dengue Hemorrhagic Fever (DHF) caused Dengue virus which transmitted through the bite of the Aedes sp. Detection of dengue virus serotypes is essential for epidemiology as well as potential disease pathogens. RT-PCR method was more effective in mosquitoes, because the virus contained in the mosquito body is passed on to the next generation (trans ovarian). The purpose of this research is to know the serotype of DHF virus accurately through vector mosquito using RT-PCR method in Mataram City, so that vector control, early diagnosis and management of DHF disease could be done quickly and precisely. This research was a laboratory explorative research with cross sectional design that determines serotype of DHF virus through vector mosquito using RT-PCR method in Mataram City. The population of this study were Aedes aegypti female mosquitoes from eggs. Collected from houses located in Community Health Center Mataram city worked area with high dengue cases: Pagesangan, Karang Taliwang, Karang Pule, Tanjung Karang, Mataram, and Selaparang especially around the house’s sufferers. The results showed that only the mosquito group from the worked area of the Mataram Community Health Center showed the ribbon image with the base pair in accordance with serotype 1 (DENGUE 1), the other negative.

scholarly journals UJI DIAGNOSTIK METODE IMUNOSITOKIMIA NS1 VIRUS DENGUE, UNTUK DIAGNOSIS INFEKSI

2018 ◽  
Vol 18 (2) ◽  
pp. 124
Author(s):  
Nafiandi Nafiandi ◽  
Ellyza Nasrul ◽  
Rismawati Yaswir
Keyword(s):  
Positive Predictive Value ◽  
Dengue Virus ◽  
Diagnostic Test ◽  
Predictive Value ◽  
Nonstructural Protein ◽  
Venous Blood ◽  
Test Method ◽  
Ns1 Protein ◽  
Rt Pcr ◽  
Cross Sectional

NS1 protein is a nonstructural protein of dengue virus which are secreted into the blood. NS1 protein could be detected in blood upto nine days after the onset of illness that almost simultaneously with the occurrence of viremia. The purpose of this study is to knowthe result of diagnostic test method of immunocytochemical NS1 by RT-PCR on dengue virus infected patients which is diagnosed at Dr.M. Djamil hospital. Padang. The method of the research uses cross sectional analytically study with consecutive sampling of patientswho diagnosed as infected with dengue virus and treated in the interne ward of Dr. M. Djamil General Hospital Padang from Januaryup to August 2011. Patient ‘s venous blood was taken about 5 mL and then centrifuged 3500 rpm and then the serum is separated andstored at-20° C until the sample is examined. The examination of NS1 serum is carried out by immunocytochemical method followedby the inspection of RNA viruses and their serotypes by RT-PCR and continued by agarose gel electrophoresis on 1.5 up to 2%. From thesixty samples obtained showed: 71.6% tested positive immunocytochemical NS1, 28.4% negative immunocytochemical NS1, 76.7%positive RT-PCR and 23.3% negative RT-PCR, 23.9% Den-1, 43.3% Den-2, 26.1% Den-3, and 6.5% Den-4. The immunocytochemicalNS1 diagnostic test obtained RT-PCR sensitivity of 85%, specificity 71%, positive predictive value 90%, and negative predictive value59%. The immunocytochemical NS1 has a quite high sensitivity, and low specificity, where as the positive predictive value is quite high,but the negative predictive value is lower than the RT-PCR for the diagnosis of dengue virus infection.

Studies on mosquito density in urban Kano: a study to calculate larval indices in municipal area of Gwale, Kano, Nigeria

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
A.B. Umar ◽  
A.H. Dankaka ◽  
M. Manjur Shah
Keyword(s):  
Local Government ◽  
Critical Level ◽  
Cross Sectional Study ◽  
Local Government Area ◽  
Mosquito Density ◽  
Sectional Study ◽  
Cross Sectional ◽  
Potential Sources ◽  
Mosquito Breeding ◽  
Water Holding

The study is carried out to standardize larval indices namely House Index, Container Index and Breteau Index and also to identify the major breeding sources of mosquitoes in the residential environment in and around the Gwale Local government area of  Kano, Nigeria. A cross-sectional study by selecting 50 houses randomly from the 6 wards of Municipality was employed. Every water holding container indoors and outdoors were counted and searched for larval presence and noted on a pretested format. In this study, 300 houses were surveyed in 21 days out of which 94.33% (283 houses) were found to have potential sources for mosquito breeding. All the entomological indices were found to be above the critical level. House Index = 28.67%; Container Index = 12.14%; Breteau Index = 64.00% showing high chances for outbreaks of mosquito borne diseases. The area is prone to mosquito borne disease like malaria and therefore warrants interventions from the competent.

Psychological Impacts of COVID-19 During the First Nationwide Lockdown in Vietnam: Web-Based, Cross-Sectional Survey Study (Preprint)

2020 ◽  
Author(s):  
Khanh Ngoc Cong Duong ◽  
Tien Nguyen Le Bao ◽  
Phuong Thi Lan Nguyen ◽  
Thanh Vo Van ◽  
Toi Phung Lam ◽  
...  
Keyword(s):  
Psychological Distress ◽  
General Population ◽  
Psychological Health ◽  
Online Survey ◽  
Survey Study ◽  
Limited Information ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Event Scale ◽  
The Impact

BACKGROUND The first nationwide lockdown due to the COVID-19 pandemic was implemented in Vietnam from April 1 to 15, 2020. Nevertheless, there has been limited information on the impact of COVID-19 on the psychological health of the public. OBJECTIVE This study aimed to estimate the prevalence of psychological issues and identify the factors associated with the psychological impact of COVID-19 during the first nationwide lockdown among the general population in Vietnam. METHODS We employed a cross-sectional study design with convenience sampling. A self-administered, online survey was used to collect data and assess psychological distress, depression, anxiety, and stress of participants from April 10 to 15, 2020. The Impact of Event Scale-Revised (IES-R) and the Depression, Anxiety, and Stress Scale-21 (DASS-21) were utilized to assess psychological distress, depression, anxiety, and stress of participants during social distancing due to COVID-19. Associations across factors were explored using regression analysis. RESULTS A total of 1385 respondents completed the survey. Of this, 35.9% (n=497) experienced psychological distress, as well as depression (n=325, 23.5%), anxiety (n=195, 14.1%), and stress (n=309, 22.3%). Respondents who evaluated their physical health as average had a higher IES-R score (beta coefficient [B]=9.16, 95% CI 6.43 to 11.89), as well as higher depression (B=5.85, 95% CI 4.49 to 7.21), anxiety (B=3.64, 95% CI 2.64 to 4.63), and stress (B=5.19, 95% CI 3.83 to 6.56) scores for DASS-21 than those who rated their health as good or very good. Those who self-reported their health as bad or very bad experienced more severe depression (B=9.57, 95% CI 4.54 to 14.59), anxiety (B=7.24, 95% CI 3.55 to 10.9), and stress (B=10.60, 95% CI 5.56 to 15.65). Unemployment was more likely to be associated with depression (B=3.34, 95% CI 1.68 to 5.01) and stress (B=2.34, 95% CI 0.84 to 3.85). Regarding worries about COVID-19, more than half (n=755, 54.5%) expressed concern for their children aged &lt;18 years, which increased their IES-R score (B=7.81, 95% CI 4.98 to 10.64) and DASS-21 stress score (B=1.75, 95% CI 0.27 to 3.24). The majority of respondents (n=1335, 96.4%) were confident about their doctor’s expertise in terms of COVID-19 diagnosis and treatment, which was positively associated with less distress caused by the outbreak (B=–7.84, 95% CI –14.58 to –1.11). CONCLUSIONS The findings highlight the effect of COVID-19 on mental health during the nationwide lockdown among the general population in Vietnam. The study provides useful evidence for policy decision makers to develop and implement interventions to mitigate these impacts. CLINICALTRIAL

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