Integrated control of Aedes albopictus in Southwest Germany supported by the Sterile Insect Technique

Background The invasive species Aedes albopictus, commonly known as the Asian tiger mosquito, has undergone extreme range expansion by means of steady introductions as blind passengers in vehicles traveling from the Mediterranean to south-west Germany. The more than 25 established populations in the State of Baden-Württemberg, Palatine and Hesse (south-west Germany) have become a major nuisance and public health threat. Aedes albopictus deserves special attention as a vector of arboviruses, including dengue, chikungunya and Zika viruses. In Germany, Ae. albopictus control programs are implemented by local communities under the auspices of health departments and regulatory offices. Methods The control strategy comprised three pillars: (i) community participation (CP) based on the elimination of breeding sites or improved environmental sanitation, using fizzy tablets based on Bacillus thuringiensis israelensis (fizzy Bti tablets; Culinex® Tab plus); (ii) door-to-door (DtD) control by trained staff through the application of high doses of a water-dispersible Bti granular formulation (Vectobac® WG) aimed at achieving a long-lasting killing effect; and (iii) implementation of the sterile insect technique (SIT) to eliminate remaining Ae. albopictus populations. Prior to initiating large-scale city-wide treatments on a routine basis, the efficacy of the three elements was evaluated in laboratory and semi-field trials. Special emphasis was given to the mass release of sterile Ae. albopictus males. Results More than 60% of the local residents actively participated in the first pillar (CP) of the large-scale control program. The most effective element of the program was found to be the DtD intervention, including the application of Vectobac® WG (3000 ITU/mg) to potential breeding sites (10 g per rainwater container, maximum of 200 l = maximum of approx. 150,000 ITU/l, and 2.5 g per container < 50 l) with a persistence of at least 3 weeks. In Ludwigshafen, larval source management resulted in a Container Index for Ae. albopictus of < 1% in 2020 compared to 10.9% in 2019. The mean number of Aedes eggs per ovitrap per 2 weeks was 4.4 in Ludwigshafen, 18.2 in Metzgergrün (Freiburg) (SIT area) and 22.4 in the control area in Gartenstadt (Freiburg). The strong reduction of the Ae. albopictus population by Bti application was followed by weekly releases of 1013 (Ludwigshafen) and 2320 (Freiburg) sterile Ae. albopictus males per hectare from May until October, resulting in a high percentage of sterile eggs. In the trial areas of Ludwigshafen and Frieburg, egg sterility reached 84.7 ± 12.5% and 62.7 ± 25.8%, respectively; in comparison, the natural sterility in the control area was 14.6 ± 7.3%. The field results were in line with data obtained in cage tests under laboratory conditions where sterility rates were 87.5 ± 9.2% after wild females mated with sterile males; in comparison, the sterility of eggs laid by females mated with unirradiated males was only 3.3 ± 2.8%. The overall egg sterility of about 84% in Ludwigshafen indicates that our goal to almost eradicate the Ae. albopictus population could be achieved. The time for inspection and treatment of a single property ranged from 19 to 26 min depending on the experience of the team and costs 6–8 euros per property. Conclusions It is shown that an integrated control program based on a strict monitoring scheme can be most effective when it comprises three components, namely CP, DtD intervention that includes long-lasting Bti-larviciding to strongly reduce Ae. albopictus populations and SIT to reduce the remaining Ae. albopictus population to a minimum or even to eradicate it. The combined use of Bti and SIT is the most effective and selective tool against Ae. albopictus, one of the most dangerous mosquito vector species. Graphical Abstract

First Report of Culicoides Biting Midges (Diptera: Ceratopogonidae) Attacking People in Italy, With the Description of Extreme Larval Breeding Sites and Diurnal Activity of Culicoides riethi

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) play a paramount role in medical and veterinary entomology worldwide, particularly as vectors of pathogens which cause animal diseases. Biting midges are also infamous for the nuisance they provoke to people involved in outdoor activities. Nonetheless, attacks to man by midges from any Culicoides species have not been reported in Italy. An entomological investigation was performed following repeated attacks to man in a nature park near Rome (central Italy). The study area is a natural degassing zone, characterized by widespread hazardous gas emissions of CO2 and H2S, with several water bodies including permanent lakes, ponds, and pools. The biting midge C. riethi Kieffer, 1914 was very active during daytime in the period April–June. The species has been identified as responsible for attacks on people in the area. An in-depth analysis of the extreme environmental conditions revealed the ability of larvae to thrive in several water bodies, characterized by an extremely low pH and a high concentration of sulfates.

Haemagogus leucocelaenus (Diptera: Culicidae), the potential wild vector of yellow fever in the border zone of northern Misiones, Argentina

Haemagogus leucocelaenus (Diptera: Culicidae) is considered the primary vector of yellow fever virus (Flaviviridae) in wild environments in South America. Previous research has defined Hg. leucocelaenus as a wild species with phytotelmata-type breeding sites. The objective of this study was to report the temporal and space occurrence of Hg. leucocelaenus at the microscale in the wild-periurban fringe through a systematic and spatially stratified sampling using 81 ovitraps between April 2019 and February 2 020 in the locality of Puerto Iguazú, Argentina. Of the total ovitraps, eight were positive for Hg. leucocelaenus, six in the wild environment and two in the periurban environment. Regarding the time distribution, 98.5% of the occurrence was concentrated in November and December 2019 towards the beginning of the rainy season. The results confirm the habitat plasticity of Hg. leucocelaenus and establish the aptitude of artificial containers as a methodology in monitoring studies, since they illustrate the potential of wild populations to deposit fertile eggs in them at least up to 300 m from the wild-periurban fringe. This work is a contribution to determine the temporal and space risk of yellow fever virus transmission in the region, based on the distribution patterns of this species as a function to the ecotone associated with forest borders and climatic variables.

KEPADATAN JENTIK Aedes aegypti SEBAGAI VEKTOR DEMAM BERDARAH DENGUE (DBD) DI DESA KALIANCAR WONOGIRI

Dengue Hemorrhagic Fever (DHF) is a disease caused by the dengue virus which is transmitted through the bite of the Aedes sp. These mosquitoes are found throughout the world and their breeding is quite fast. Density of larvae found in breeding sites in an area. This density can be measured by entomological indicators. This larval density measurement can indicate the potential for larvae in Kaliancar Village, Selogiri District, Wonogiri Regency. This research is an observational study (survey) with cross sectional. The sampling technique used is simple random sampling with single larvae method. The samples of this study were 100 houses of residents of Kaliancar Village RW 01, RW 03, RW 04 and RW 05. The results showed that the HI value was 20%, CI 7,22%, BI 20%, ABJ 80% and DF 3,66. The conclusion of this study is that the larval density in Kaliancar Village, Selogiri District, Wonogiri Regency is classified as moderate because the DF value is on a scale of 3 to 4 with an average of 3,66.

Potensi Culex quinquefasciatus sebagai Vektor Filariasis dan Kondisi Lingkungan di Kota Pekalongan

Pekalongan City was still an endemic area of Lymphatic Filariasis (LF). Twice cycles ofMass Drug Administration (MDA) had been implemented, but the Microfi laria rate (Mf rate) wasstill more than 1%. This observational research aimed to study the potential of Culex quinquefasciatusas a vector of LF in Pekalongan City. A Cross-sectional design was chosen as an approach in compilinginformation related to environmental factors and mosquitoes. The population of this research washouses located in Jenggot and Kertoharjo village with thirty-one houses, located around fi lariasiscases, purposively selected as samples. Variables studied in this research were environmental factorsand mosquito vectors. Data collection using observation, and laboratory examination throughmosquito dissection. Data would be analyzed descriptively. This study found that there were 8 Culexquinquefasciatus tested positive L3 fi larial worm (infective rate 4.39%). There were 74.2% of houseshad mosquitoes’ breeding sites around them. The breeding sites were found at domestic waste disposal,drainage in front of the house, and infi ltration well for liquid waste. As much as 86.2% of the breedingsites contained mosquito larvae. This research concluded that Cx. quinquefasciatus was confi rmedpositive fi laria worm thus establish as mosquito vector for Lymphatic Filariasis in Pekalongan City.The breeding sites related to the mosquito development were small water bodies, drainage in front ofand around the house.

Species Composition, Abundance and Population Structure of Malaria Vectors in Two Villages of Sudan

BackgroundFrequent monitoring of mosquito vector population is a strategy of great importance for reducing risks of disease occurrence. In Sudan, malaria is still a big threat to public health. Insecticide-based control has been undertaken for years, but there is no noticeable decrease of malaria infection nationwide.ObjectiveTo overcome this situation, a better understanding of the breeding ecology of the vectors is relevant. Here, we investigate the species composition of malaria vectors, seasonal abundance and population structure in two different villages.MethodologyMonthly samplings were performed in Abu Algoni (Sennar State) and Algerif West (Khartoum State) from June 2010 to May 2011. During each visit, immature stages were collected from potential breeding sites using dipping technique. In addition, adults were collected indoors from houses by aspiration and indoor pyrethrum spray methods. Mosquitoes were identified morphologically, the Anopheles gambiae complex diagnosed using PCR and the physiological status of females determined based on appropriate techniques. Environmental parameters namely temperature, rainfall and humidity were measured.ResultsA total of 4,932 mosquitoes comprising of 3047 larvae and 1885 adults (males and females combined) were sampled. Of these, 88.9% were collected from Abu Algoni while 11.1% were from Algerif West. Two species, An. rufipes and An. arabiensis were encountered. Anopheles rufipes was only found in Abu Algoni, while the latter was found in both villages, where it represented more than 99% of the total collection.Mosquitoes were found breeding in many types of places including canals, temporary pools of water, animal hooves, water from broken pipes, and water storage containers. No significant correlation was found between female and temperature (p>0.05). Significant correlation difference was observed between number of females of An. arabiensis and rainfall (p<0.05) and humidity (p<0.01).ConclusionsAnopheles arabiensis is the only member of An. gambiae complex detected in the present study. Seasonal abundance of An. arabiensis was observed with most during the wet rainy season in both villages. This could be associated with the availability of more breeding sites created by the rainfall. The majority were parous which indicates high survival rates and thus high vectorial capacity in transmitting malaria.

Characteristics Environmental and Anopheles Larva Species In High And Low Clinical Malaria Cases In The Landak District of West Kalimantan Province

Malaria remains a health problem in Indonesia. West Kalimantan is a malaria endemic area with high and lowincidence. Landak District is one of the malaria endemic area. Malaria cases were found in the areas around illegalgold mining and oil palm plantations. The aims of this study were to describe the characteristics of the breeding sitesand species of Anopheles larvae found in high malaria cases area, namely Amboyo Utara Village and low clinicalmalaria cases, area namely Mandor Village. This research is a descriptive research with cross sectional design. Thesamples were Anopheles larvae collected with Accidental sampling technique in the breeding sites. Environmentalcharacterization of breeding sites were physical characteristic including water temperature and sun exposure,chemical characteristic including water pH and salinity, and biological characteristics including water biota. Theresults of this study ware environmental characteristics that have the potential to breed Anopheles mosquitoes inAmboyo Utara Village, including water temperature 26-30C, shandy, water pH 5.0-7.6, salinity 0.2-1.0 ppt, biotaswater hyacinth, grass and tadpole. The Mandor village, water temperature 29-30 ºC, shandy, pH of 6.9-8.0, salinity of0.5 ppt, water biota grass. Anopheles species found in Amboyo Utara village were larvae of An. vagus (94.30%), An.tessellatus (3.42%), An. subpictus (1.62%), An. indefinitus (0.81%) and An. maculatus (0.81%). Characteristics ofbreeding sites in Mandor village were larvae of An. maculatus (11.11%), An. subpictus (3.70%), and An. vagus(85.18%). The conclusion of this study was that di erent species found at breeding sites with di erent environmentalcharacteristics in both high and low malaria areas in Landak District, West Kalimantan Province.

Breeding record of Black-headed Ibis Threskiornis melanocephalus (Aves: Threskiornithidae) at Mavoor wetland, Kozhikode District, Kerala, India

Black-headed Ibis Threskiornis melanocephalus is a nomadic and medium sized waterbird foraging in shallow water habitats and is listed under Near-Threatened category of IUCN. Though it has a widespread distribution within Kerala, little is known about their breeding sites and their ecology. In Kerala, only three nesting sites were reported so far. Present study found an additional nesting site in Mavoor wetland, which is the first record in Kozhikode district and fourth site for Kerala.

Temporal Viability of Aedes aegypti and Aedes albopictus Eggs Using Two Hygroscopic Substances as Preservatives under a Sterile Insect Technique (SIT) Program in Southern Mexico

Dengue and other Aedes-borne diseases have dramatically increased over the last decades. The Sterile Insect Technique (SIT) has been successfully used as part of integrated pest strategies to control populations of insect-plant and livestock pests and is currently being tested as a potential method to reduce mosquito populations in an environmentally friendly approach. However, during the mass rearing steps needed to produce millions of mosquitoes, egg storage and preservation are essential for a certain amount of time. Eggs of Aedes aegypti have a chorionic pad that functions as a sticky substance to glue them onto the inner walls of larval breeding sites. The chorionic pad is chemically made of hyaluronic acid, a hygroscopic compound, responsible to protect them from desiccation over time. Two commercial products with hygroscopic properties, hydrolyzed collagen, and Hyalurosmooth®, both were tested to assess their ability to prolong egg life storage for A. aegypti and A. albopictus. Results showed that 85–95% of Ae. aegypti eggs were able to hatch up to week 8 after being treated with both hydrophilic compounds, compared with the control 66.3%. These two substances showed promising effects for keeping Ae. aegypti eggs viable during prolonged storage in mass rearing insect production focused on vector control SIT programs.

Factors Associated with a Malaria Outbreak at Tongogara Refugee Camp in Chipinge District, Zimbabwe, 2021: A Case-Control Study

Background: Malaria is a leading cause of morbidity and mortality among forcibly displaced populations including refugees, approximately two-thirds of whom reside in malaria endemic regions. Data from the rapid disease notification system (RDNS) reports for Manicaland Province in Zimbabwe showed that despite implementation of malaria control initiatives, there was an increase in number of malaria cases above action thresholds at Tongogara Refugee Camp in Chipinge District during weeks 12-14. We investigated the malaria outbreak describing the outbreak by person, place and time, assessing malaria emergency preparedness and response and appropriateness of case management. We also determined the factors associated with contracting malaria to enable the formulation of appropriate interventions, establish control and prevent future malaria outbreaks among this vulnerable population.Methods: We conducted a 1:1 unmatched case control study involving 80 cases and 80 controls using interviewer-administered questionnaires at household level. Data was entered using Epi Data version 3.1 and analyzed using Epi InfoTM version 7.2.4 to generate medians, proportions, odds ratios and their 95% confidence intervals.Results: Malaria cases were distributed throughout the 10 residential sections within Tongogara Refugee Camp, the majority being from section 7, 28/80 (35%). Despite constituting 11% of the total population, Mozambican nationals accounted for 36/80 (45%) cases. Males constituted 47/80 (59%) among cases versus controls 43/80 (54%), p=0.524. Median age for cases was also lower compared to controls; 15 years [Interquartile range (IQR), 9-26] versus 17 years (IQR, 10-30). Several natural and manmade potential vector breeding sites were observed around the camp. Risk factors associated with contracting malaria were engaging in outdoor activities at night [AOR 4.26 (95% CI, 1.43-12.68)], wearing clothes that do not cover the whole body [AOR=2.74 (95% CI 1.04-7.22) while sleeping in a refugee housing unit reduced the risk of contracting malaria [AOR=0.18 (CI, 0.06-0.55)]. Conclusions: The malaria outbreak at Tongogara Refugee Camp reemphasizes the role of behavioral factors in malaria transmission. We recommend intensified health education to address human behaviors that expose residents to malaria and habitat modification with larviciding to eliminate mosquito breeding sites.