A model for the Aedes aegypti lifecycle is developed that takes into account temperature-dependent maturation and death rates for several life stages, wet and dry egg oviposition with flooding, as well as three classes of larval habitat with different temperature profiles: outdoor (subject to external temperature fluctuations, human-inhabited), indoor (temperature moderated, human-inhabited, interior), and enclosed (temperature moderated, human free, exterior). An equilibrium analysis shows that the temperature range of outdoor viable equilibrium populations aligns closely with reported risk levels. Temperature patterns for El Paso, Texas; New York, New York; New Orleans, Louisiana; Orlando, Florida; and Miami, Florida, are considered. In four of these locations (all but New York), enclosed habitats can support mosquito populations even if all outdoor and indoor habitats are removed. In two locations (El Paso and New York) the model shows that in spite of the disappearance of adult mosquitoes during colder temperatures, populations reach seasonal steady state due to the survival of eggs. The results have implications for both vector and disease control.

Currently, dengue control relies largely on reactive vector control programmes. Proactive vector-control using a rational, well-balanced integrated vector management approach may prove more successful for dengue control. As part of the development of a cluster randomized controlled epidemiological trial, a study was conducted in Johor Bahru, Malaysia. The study included one control site (three buildings) and three intervention sites which were treated as follows: targeted outdoor residual spraying only (TORS site, two buildings); deployment of autodissemination devices only (ADD site, four buildings); and the previous two treatments combined (TORS + ADD site, three buildings). The primary entomological measurement was per cent of positive ovitraps—ovitrap index (OI). The effect of each intervention on OI was analyzed by a modified ordinary least squares regression model. Relative to the control site, the TORS and ADD sites showed a reduction in the Aedes OI (−6.5%, P = 0.04 and −8.3%, P = 0.10, respectively). Analysis by species showed that, relative to control, the Ae. aegypti OI was lower in ADD (−8.9%, P = 0.03) and in TORS (−10.4%, P = 0.02). No such effect was evident in the TORS + ADD site. The present study provides insights into the methods to be used for the main trial. The combination of multiple insecticides with different modes of action in one package is innovative, although we could not demonstrate the additive effect of TORS + ADD. Further work is required to strengthen our understanding of how these interventions impact dengue vector populations and dengue transmission.

The control of dengue constitutes a great challenge for public health; however, the methods normally used have shown themselves to be insufficient to keep the indices of infestation of Aedes aegypti under control. Recently, beyond the large number of cases and deaths associated with dengue, new risks have arisen such as those represented by chikungunya fever and Zika. In the light of the great significance of these problems within the public health context, two areas in a municipality in the interior of the State of São Paulo, Brazil were selected in 2014. One of them, Bairro Cidade Nova, was submitted to the conventional method of nebulization with portable equipment, and the other, Bairro Jardim Europa, received the application of the insecticide by means of heavy-equipment coupled to the vehicle. During the project, 1355 mosquito eggs were collected, 1105 of them in Bairro Cidade Nova and 205 in Bairro Jardim Europa. After the applications with heavy-equipment in the months of March and April, the number of cases of the disease reported in the month of April for Bairro Jardim Europa was less than half that of Bairro Cidade Nova, which had received the conventional treatment. The nebulization with the heavy-equipment may constitute a viable and effective strategy for achieving better results in the control of Ae. aegypti.

Dengue, one of the most important mosquito-borne diseases, is a major international public health concern. This study aimed to assess potential dengue infection risk from Aedes aegypti in Kaohsiung and the implications for vector control. Here we investigated the impact of dengue transmission on human infection risk using a well-established dengue–mosquito–human transmission dynamics model. A basic reproduction number (R 0)-based probabilistic risk model was also developed to estimate dengue infection risk. Our findings confirm that the effect of biting rate plays a crucial role in shaping R 0 estimates. We demonstrated that there was 50% risk probability for increased dengue incidence rates exceeding 0·5–0·8 wk−1 for temperatures ranging from 26°C to 32°C. We further demonstrated that the weekly increased dengue incidence rate can be decreased to zero if vector control efficiencies reach 30–80% at temperatures of 19–32°C. We conclude that our analysis on dengue infection risk and control implications in Kaohsiung provide crucial information for policy-making on disease control.

Bluetongue is a disease of major economic concern in Europe. Its causative agent, bluetongue virus (BTV), is transmitted by several Culicoides species (mainly Culicoides imicola and Culicoides obsoletus in Europe). The application of insecticides on animals may reduce transmission of BTV, however, no formulation is currently licensed specifically against Culicoides midges. The present study assesses the susceptibility of C. obsoletus to deltamethrin using an adapted World Health Organization (WHO) susceptibility test. Midges were exposed to different dosages of deltamethrin for 1 h, and mortality after 1 h and 24 h was recorded. Results indicated that deltamethrin is highly toxic to C. obsoletus since a dose of 1·33×10−4% was enough to kill 50% of the population (LD50) in 24 h. The deltamethrin concentration needed to kill 90% of the population (LD90) was 5·55×10−4%. The results obtained in the present work could help to create a system that can be used to assess insecticide resistance and susceptibility of Culicoides biting midges.

Infection with dengue, the most prevalent mosquito-borne virus, manifests as dengue fever (DF) or the more fatal dengue haemorrhagic fever (DHF). DHF occurs mainly when an individual who has acquired antibodies to one serotype is inoculated with another serotype. It was reported that mosquito control may have increased the incidence of DF and DHF due to age-dependency in manifesting these illnesses or an immunological mechanism. Tetravalent dengue vaccine is currently being tested in clinical trials. However, seroconversions to all four serotypes were achieved only after three doses. Therefore, vaccines may predispose vaccinees to the risk of developing DHF in future infections. This study employed an individual-based computer simulation, to emulate mosquito control and vaccination, incorporating seroconversion rates reported from actual clinical trials. It was found that mosquito control alone would have increased incidence of DF and DHF in areas of high mosquito density. A vaccination programme with very high coverage, even with a vaccine of suboptimal seroconversion rates, attenuated possible surges in the incidence of DF and DHF which would have been caused by insufficient reduction in mosquito abundance. DHF cases attributable to vaccine-derived enhancement were fewer than DHF cases prevented by a vaccine with considerably high (although not perfect) seroconversion rates. These predictions may justify vaccination programmes, at least in areas of high mosquito abundance. In such areas, mosquito control programmes should be conducted only after the vaccination programme with a high coverage has been initiated.

The effects of exposure to infective larvae on the antibody response to a cocktail of specific recombinant antigens of Onchocerca volvulus and to a worm extract were evaluated by comparing the responses of individuals from a vector controlled area with those from an area of continuing transmission by ELISA. Individuals from the vector controlled areas were found to have reduced responses to both antigen preparations. Amicrofilerdermic (mf–) individuals from the area of vector control exhibited significantly lower total and subclass IgG responses to the worm extract. In contrast, the responses to the cocktail of specific recombinants were significantly reduced in individuals from the area of vector control who were still microfilerdermia positive (mf+). The distribution of IgG subclass specific responses was similar to both antigen preparations, both dominated by the IgG4 and IgG1 subclasses. IgG1 responses to the worm extract remained elevated in the vector controlled individuals but IgG4 was significantly reduced in the mf – individuals. Both subclasses reflected the total IgG response to the cocktail of recombinants and were significantly reduced in individuals from the vector controlled area, when compared to individuals from the hyperendemic area. IgG1 responses to the cocktail of recombinants are significantly lower than IgG4 in all individuals and virtually absent in individuals from the vector-controlled area. Measuring total IgG and IgG4 is more sensitive than IgG1 in detecting infection, 100 or 97% respectively, but they remain elevated in the individuals from the vector controlled areas even after 8–10 years interruption of transmission. These results have important implications for the serological monitoring of control programmes in individuals who have previously been infected.

The study reported here evaluated the distribution, relative abundance, and malaria transmission potential of Anopheles mosquitoes at 30 sites representing different ecological strata in western Kenya. Seasonal variation in anopheline densities and transmission potential, as expressed by Entomological inoculation rates (EIR), was investigated. Of the 6491 indoor resting anopheline mosquitoes collected at the 30 sites, 91.3 % (n = 5926) were An. gambiae s.l. and 8.7 % (n = 565) were An. funestus with an average house density of 6.58 and 0.63, respectively. Analysis of the data indicated significant variation in mosquito densities between study sites, species and season. High densities of both An. gambiae and An. funestus were recorded in the northern and northeastern parts of the district, while generally low densities were recorded in the south. Anopheles gambiae s.s. and An. arabiensis comprised 60.3 % (n = 3573) and 39.7 % (n = 2352) of the total number of An. gambiae s.l. mosquitoes collected, respectively. The composition of the An. gambiae s.l. sibling species showed temporal and spatial variation. Entomologic inoculation rates were estimated at 1.55 and 0.12 infective bites per person per month for An. gambiae s.l. and An. funestus, respectively. This study reveals considerable seasonal and site-specific variation in vector distribution, composition and transmission potential. Application of control interventions must therefore consider seasonal variations since the vectorial system changes quite rapidly over a short period of time.

This paper provides an overview of disaster public health preparedness, response, and recovery activities with particular reference to examples that have occurred in California. It discusses the public health considerations from two aspects: 1) general public health effects; and 2) public and environmental health control measures. The latter discussion is divided into: 1) drinking water; 2) human wastes; 3) food; 4) personal hygiene; 5) mass care and shelter; 6) solid waste and debris; 7) hazardous materials; 8) injury prevention programs and public health information; 9) vector control; and 10) disease control and surveillance. Two tables summarize the disaster medical and health functions as they relate to public health.

This paper is based on experiences obtained during a joint enterprise between the Social Science Interface Research Unit, of the Crop Pests Research Programme, and the Livestock Ticks Research Programme at ICIPE. Topics bearing on technology design and development are emphasized.

The resource-poor farmer as conceptualized within ICIPE and reinforced by research experience, is by definition a person who operates a diversified system of production in which food security concerns and cash income intakes are crucial.

The family/household provides most of the labour required in production in African farming communities. For this reason, their labour investment into the adoption of novel activities or technological innovation and their assessment of the value of such innovations requiring changes in their normative practice, is appraised primarily in terms of the returns they would get for the additional labour input.

It is noteworthy that much of the so-called family labour is, in fact, female labour. It is therefore arguable that the perception of the women of technological inputs and innovations as profitable, is crucial for the successful adoption and social acceptance of novel technology.

Although agricultural land is in increasingly short supply, it would appear that the crucial limiting factor in production is not a shortage of land per se, since a good number of households do not fully exploit all the agricultural land at their disposal. Labour, and/or cash income to secure additional labour, appears to be the most important constraint to production. This tends to suggest that for future technological interventions in agricultural systems of the rural poor, consideration will have to be given to inputs which optimize the use of family/household labour.

The escalating population growth suggests that focus on women's health and incomes could significantly and qualitatively improve the prospects for the adoption of new and improved technology in areas such as pest and vector control.

Ground spraying trials with different dosages of deltamethrin wettable poweder (NRDC 161) were carried out against G. palpalis (s.l.), vector of sleeping sickness, in January and November 1981 in the Bouaflé human trypanosomiasis focus, Ivory Coast. Three dosages have been tested: 60 g of active ingredient (a.i.) per ha at a concentration of 0.08% in January; and 20 and 12 g of active ingredient per ha in November at 0.027 and 0.016%, respectively. Each dosage has been applied once as a residual spray; spraying apparatus used was the atomiser Solo Port 423. The knock-down and short-term effects of the insecticide were very satisfactory: 90–98% reduction in apparent density of the vector was obtained during the first 2 months after treatment with all the three dosages applied. In the long term, 2–4 months after spraying, more than 95% reduction in apparent density of G. palpalis (s.l.) was achieved even with the lowest dosage of 12 g (a.i.)/ha. The highest dosage of 60 g (a.i.)/ha does not seem to increase significantly the persistence of the insecticide nor the mortality rate of the vector in the study area. In order to reduce the cost of a tsetse control programme and also to minimise insecticide impact on non-target organisms, it is therefore recommended that deltamethrin w.p. be applied at the lower dosage of 12 g (a.i.)/ha in residual ground spraying.