Journal of Vector Borne Diseases最新文献

Background objectives: Malaria remains a complex challenge in India due to its diverse epidemiology, multi-ethnic population, and multiplicity of malaria vectors. While progress has been made in reducing malaria nationally, persistent pockets hinder elimination efforts. These challenges include hidden reservoirs, inadequate healthcare, suboptimal surveillance, non-compliance, and subclinical infections. Shortage of grassroot level and primary care health staff, transportation issues and general inaccessibility and unavailability of healthcare services are additional challenges.

Methods: Mobile healthcare vans have been tried and found useful in enhancing healthcare availability in several health conditions in different settings. Nuh district in Haryana, India is a malaria endemic region; it is indeed one of the districts included by India's NITI Aayog in the Aspirational Districts Programme, a government initiative that focuses on rapidly transforming and developing the most underdeveloped districts in country. With an aim to improve the healthcare seeking behavior of malaria-endemic community of selected villages of Nuh district, we carried out a study using interventions in two villages of the district, that had mobile malaria clinics and toll-free telephone services in enhancing healthcare access.

Results: We found that Sangel village had higher literacy rates (60.6%) as compared to 39.4% in Naushera. Similarly, the unemployment rate was higher for Naushera. It the mobile malaria clinic was deployed from December 2019 to July 2020 and a total of 269 phone calls were received from both the villages. A similar number of rapid tests and microscopy smears were examined and all were negative for malaria. The febrile patients were referred to the nearest healthcare facility.

Interpretation conclusion: The study shows that the community is open to using these healthcare interventions. These initiatives of mobile malaria clinics and toll-free telephone services can bridge healthcare gaps, especially in malaria-endemic regions, aligning with India's malaria elimination and equitable healthcare access goals.

Backgrounds objectives: Dengue fever, transmitted by Aedes mosquitoes, is a significant public health concern in Nepal. An extensive Knowledge, Attitude, and Practice (KAP) survey related to Aedes mosquitoes and prevention of dengue was conducted along the route from Matihani (62 m above sea level) to Kalinchok (3840 m asl) in central Nepal. This research examined residents' awareness of Aedes mosquitoes and the diseases they transmit, aiming to support the World Health Organization's national and global fight against mosquito-borne diseases.

Methods: The survey included 550 participants aged 18-75 years (249 males and 201 females). Door-to-door campaigns were conducted to gather data on knowledge scores, practices, and attitudes about Aedes mosquitoes using a standard structured questionnaire.

Results: Findings of this study revealed a moderate level of knowledge across the study area, with a mean knowledge score of 5.525±2.58 (correct answer rate of 46.05%). While 99.6% of respondents were aware of dengue transmission by mosquitoes, only 64.5% were able to report Aedes mosquitoes as the key transmitter. Less than one-third of the participants (27.8%) were familiar with black-and-white stripes in Aedes. Additionally, only 36.7% were knowledgeable about the day-biting behavior of Aedes mosquitoes.

Interpretation conclusion: This KAP survey provides valuable insights into community understanding of Aedes mosquitoes and dengue prevention practices associated with various Nepalese communities residing in low to high altitudes of central Nepal. These findings can be adopted to address the increasing health burden faced by countries with low-to-high altitude regions within the Hindu Kush Himalayas.

Background objectives: Mosquito-borne diseases are a major health issue among communities in Asia, and dengue has grown up as a serious public health concern in Sri Lanka with varying magnitude since 1960. With the realization of the failures and limitations of current vector control strategies, the authorities are moving towards simple, low-cost, and eco-friendly vector management methods. Thus, the present study was devised to evaluate the potential densities of mosquito natural enemies in natural water habitats in Galle district, Sri Lanka, and to investigate the feeding efficacy of prominent mosquito natural enemies on main dengue vectors ( Aedes sp.) in a laboratory setting.

Methods: The survey was carried out using eight sentinel sites in Galle district, and samples of mosquito natural enemies and mosquito larvae were collected, and then they were identified using taxonomic keys.

Results: Study records, the aquatic insects of Family Hydrometridae, Belostomatidae, Notonectidae, Nepidae, Ranatridae, and Corixidae as dominant mosquito natural enemies, and Libellulidae and Dytiscidae insects as sub-dominant families. The highest density of the family Hydrometridae was recorded in rural, natural inland, and rocky study sites. The order Hemiptera was recorded as the key order of the mosquitoes natural enemies in Galle district. The family Hydrometridae had the highest density of recorded mosquito natural enemies.

Interpretation conclusion: Aedes aegypti and Ae. albopictus were recorded as abundant vector mosquitoes. Family Nepidae is the most effective natural mosquito predator on Ae. aegypti and Ae. albopictus, and this knowledge will be vital for implementing future biological control strategies for Aedes vectors in Sri Lanka.

Background objectives: Aedes aegypti and Aedes albopictus are two sympatric mosquito species that compete with each other for resources when their breeding habitats overlap. This study examines what happens when sympatric Aedes aegypti and Aedes albopictus mosquitoes' mate with each other and other species by looking at insemination rates, fecundity, and hatchability rate.

Methods: We performed controlled mating experiments in laboratory setting, assessing both conspecific and interspecific crosses. We measured insemination rates, egg numbers, and hatching success to examine the reproductive interference dynamics between these two distinct mosquito species.

Results: In the context of conspecific mating, it was observed that both female Ae. aegypti and Ae. albopictus exhibited high insemination rates, with percentages of 98% and 94%, respectively. However, interspecific mating exhibited interesting asymmetries: Ae. albopictus males achieved a notable insemination success rate of 28% when mating with Ae. aegypti females, while Ae. aegypti males achieved only 8% insemination success with Ae. albopictus females. Additionally, females that mated with interspecific males had reduced production of viable eggs compared to conspecific mating. Most notably, interspecific mating resulted in the production of infertile eggs, while conspecific mating led to successful hatching.

Interpretation conclusion: The study reveals that, Ae. aegypti and Ae. albopictus can asymmetrically interfere with each other's reproduction, causing a 'satyr' effect. This understanding of interspecific competition and reproductive interference in these mosquito species could impact their coexistence in shared breeding habitats.

Background objectives: Biological approaches for vector mosquito control such as sterile insect technique (SIT) requires sterilization of male mosquitoes through specific radiation doses for sterility induction in males. Under the SIT program, the males used must be compatible with the wild males in vigor, flight and selection of mate. Much of this potential is determined by the diet provided in the larval stages and optimizing the irradiation doses that cause complete sterility but have very minimal effect on the lives of irradiated males. The current study is designed to evaluate gamma radiation doses for inducing sterility in male Aedes aegypti mosquitoes with a genomic background from Pakistan (Swat district) and to assess the effects of radiation exposure on the competency of irradiated males and other life traits of irradiated mosquitoes.

Methods: Sterilization of 17-hour-old male pupae (groups of 50 pupa/cup in three replicates) of the Ae. aegypti Swat strain was conducted using radiation doses of 30, 60, 70, 90, and 105 gray (Gy) from (Co60) at the Nuclear Institute for Food and Agriculture (NIFA) in Peshawar, Pakistan. Post-irradiated pupae were released in adult cages. Virgin females of the same cohort were released (1:1) to mate with the irradiated males. Mortality, longevity, mating competitiveness of males, and female fecundity were recorded.

Results: An average of 71 eggs per female was recorded in control with 86% hatch rate. Individual females mated with a 60 Gy treated males produced 60 ± 0.6 eggs per female with 17% hatch rate, and those mated with 70 Gy males produced 42 ± 0.01 eggs with a nil hatch rate, whereas females mated with males treated with ≥70 Gy doses did not reproduce to next generation. Females in groups of 50 mated with 60, 70 Gy treated males (equal pairs), produced 369±1.3 and 98±0.01 eggs with 15% and zero hatch rate. Significant dose dependent reduction in longevity was observed for >30 Gy doses. The matting competence of irradiated males was about half that of un-irradiated males.

Interpretation conclusion: Aedes aegypti with a Pakistani genomic background treated with a ≥70 Gy dose of gamma radiation induced complete sterility in males and provided the first- step foundation for SIT application in Pakistan. Further extensive studies are required to optimize the SIT techniques so that fully sterile males with very minor quality changes can be produced on large scales for field trials.

Background objectives: Leishmaniasis is caused by various species of parasite Leishmania. Approximately twenty of them are pathogenic to mammals. In Sri Lanka, cutaneous leishmaniasis (CL) is an established vector-borne disease. CL originates and spreads mainly through sandfly bite in many endemic countries. The aim of the present study was to compare the geographical distribution and demographic features of CL cases in Hambantota district, Sri Lanka in 2014 and 2016.

Methods: The patients who were presented to the Tangalle Base Hospital from June to December in 2014 and 2016 were examined and a descriptive study was carried out using a structured-questionnaire. Slit-skin smears were collected from each patient, Giemsa-stained and examined under the light microscope to identify Leishmania amastigotes.

Results: Out of 256 and 314 suspected CL patients, 156 and 155 were identified positive for the year 2014 and 2016, respectively. Out of 12 District Secretary Divisions (DSD) in Hambantota district, the highest number of CL cases, 85 and 86 was reported from Tangalle DSD in 2014 and 2016 respectively. Number of identified CL patients in Beliatta DSD had increased from 50 to 67 during the study period. In both years, majority of CL patients were ≥50 years old with males more infected than females. Although CL association with occupations were insignificant, housewives were the highly (23%) infected occupants in this area.

Interpretation conclusion: Based on the present findings, geographical distribution within DSDs in Hambantota district had changed. This emphasizes the importance of CL as a health problem in Hambantota district.

Background objectives: Following World Health Organization (WHO) plans for thirty-five malaria-endemic countries, Indonesia will eliminate malaria by 2030. As one of the Indonesian provinces, West Java targeted subnational malaria elimination in 2022. This article aims to describe malaria surveillance data and elimination programs, including weaknesses in sustaining the program.

Methods: This study used secondary data from malaria surveillance information system regencies/cities' case reports for 2019-2022 and achievement data of sub-national malaria elimination certification from each regency/city from 2014-2022. The data was confirmed from the evaluation study document, analysis of reported cases, and interviews.

Results: Most cases were confirmed by microscopic examination (84.1% in 2021 and 94.4% in 2022) and rapid diagnostic tests (57% in 2019 and 58.1% in 2020). Malaria is more prevalent among men (93% in 2019, 95% in 2020, 96% in 2021, and 95.9% in 2022) and productive ages of 15-64 years (98.8% in 2019, 100% in 2020, 99.2% in 2021, and 98.8% in 2022), frequently occurs in the military (56.3% in 2019, 75.7% in 2020, 45.2% in 2021) and police (40.5% in 2022), often uses passive case detection for identifying cases (97.9% in 2019 and 2020, 95.2% in 2021, and 97.6% in 2022), and the majority undergo inpatient treatment (86.4% in 2019, 81.7% in 2021, and 82.6% in 2022). Most positive cases originated from imported cases, and last indigenous cases were still found in 2019. Plasmodium vivax dominated malaria cases and and relapses were high (55.0% in 2020, and 47.3% in 2022).

Interpretation conclusion: All regencies/cities have obtained sub-national malaria elimination certification in 2022. West Java has the potential to be verified for Java-Bali sub-national malaria elimination targeted in 2023, albeit cases of imported malaria still occur. It is imperative to address the issue of imported cases transitioning into locally transmitted cases (introduced) by effective coordination across all regencies/cities and inter-provincial efforts.

Background objectives: Peptides isolated from different sources of plants have the advantages of specificity, lower toxicity, and increased therapeutic effects; hence, it is necessary to search for newer antivirals from plant sources for the treatment of dengue viral infections.

Methods: In silico screening of selected plant peptides against the non-structural protein 1, NS3 protease domain (NS2B-NS3Pro) with the cofactor and ATPase/helicase domain (NS3 helicase domain/NS3hel) of dengue virus was performed. The physicochemical characteristics of the peptides were calculated using Protparam tools, and the allergenicity and toxicity profiles were assessed using allergenFP and ToxinPred, respectively.

Results: Among the tested compounds, Ginkbilobin demonstrated higher binding energy against three tested nonstructural protein targets. Kalata B8 demonstrated maximum binding energy against NSP-1 and NSP-2, whereas Circulin A acted against the NSP3 protein of dengue virus.

Interpretation conclusion: The three compounds identified by in silico screening can be tested in vitro, which could act as potential leads as they are involved in hampering the replication of the dengue virus by interacting with the three prime non-structural proteins.

Background objectives: Malaria remains a major public health concern in Nigeria and the vector (Anopheles species) can only be controlled effectively by having good knowledge of its composition and potential for disease transmission. This work aimed at surveying indoor malaria vectors and, Knowledge, Attitudes, and Practices (KAP) in relation to disease transmission in Toro LGA, Bauchi State, Nigeria.

Methods: Mosquitoes were collected by Pyrethrum Spray Catch (PSC) between October and December 2019 and were morphologically identified using standard keys. Blood samples were collected from individuals who slept in the rooms where PSC was conducted. Thick and thin blood smears were made for malaria parasite examination. Questionnaires were administered to 120 participants for the KAP studies.

Results: Ninety-seven Anopheles mosquitoes were collected and identified as Anopheles gambiae 76 (78.35%), An. funestus 20 (20.62%) and An. coustani 1(1.03%). The overall malaria prevalence was 15.8%. KAP studies revealed that measures and treatment-seeking behaviours against malaria varied significantly (P<0.05) among the respondents. Sleeping under a net 55 (45.8%) and use of insecticides 24 (20.0%) were some of the preventive measures highlighted while the treatment-seeking behaviours included visit to a pharmacy 74 (61.7%) and use of local herbs 11 (9.2%).

Interpretation conclusion: This work revealed that An. gambiae and An. funestus are predominant malaria vectors in the area. The KAP information demonstrated fair knowledge about the disease by the respondents. Therefore, public enlightenment about malaria prevention, control and treatment is recommended to address the few but highly negative impact knowledge gaps about malaria.