Jazem A. Mahyoub

An update on the incidence of dengue gaining strength in Saudi Arabia and current control approaches for its vector mosquito

BackgroundThe cases of dengue reported earlier in the late 1990s from the Kingdom of Saudi Arabia (KSA) occurred in the cities of Jeddah and Makkah. Although the kingdom has ample financial resources to establish effective control measures for the dengue vector, numerous cases of dengue occur and fluctuate in numbers from year to year. This necessitates a serious review of the current vector control strategies being practiced in order to identify the existing shortcomings. This short report provides an update on epidemiology of dengue in KSA (specifically in cities of Jeddah and Makkah) with a critical look at the current vector control strategies.FindingsIn 2013, 4411 cases of dengue were reported, with 8 cases of mortality. This number of dengue incidence was four times higher compared to 2012. In 2013, the highest number of 1272 dengue cases was reported in May, while the lowest number (37) of cases was reported in September.ConclusionsIt is evident that the control strategies of the dengue vector presently employed are inadequate. There seems to be serious deficiencies in following proper scientific procedures during field application(s) of control materials against the vector as is evident by the increases in the number of dengue cases as well as frequent outbreaks of the vector mosquito populations. In this review, some specific suggestions are made to draw attention to the relevant KSA authorities of the possible reasons behind unsuccessful control results and as to how to improve the strategy of dengue vector control in the kingdom.

Household survey of container-breeding mosquitoes and climatic factors influencing the prevalence of Aedes aegypti (Diptera: Culicidae) in Makkah City, Saudi Arabia

OBJECTIVE To investigate the prevalence of container breeding mosquitoes with emphasis on the seasonality and larval habitats of Aedes aegypti (Ae. aegypti) in Makkah City, adjoining an environmental monitoring and dengue incidence. METHODS Monthly visits were performed between April 2008 and March 2009 to randomly selected houses. During each visit, mosquito larvae were collected from indoors and outdoors containers by either dipping or pipetting. Mosquitoes were morphologically identified. Data on temperature, relative humidity, rain/precipitations during the survey period was retrieved from governmental sources and analyzed. RESULTS The city was warmer in dry season (DS) than wet season (WS). No rain occurred at all during DS and even precipitations did fall, wetting events were much greater during WS. Larval survey revealed the co-breeding of Aedes, Culex and Anopheles in a variety of artificial containers in and around homes. 32 109 larvae representing 1st , 2nd, 3rd, and 4th stages were collected from 22 618 container habitats. Culicines was far the commonest and Aedes genus was as numerous as the Culex population. Ae. aegypti larval abundance exhibited marked temporal variations, overall, being usually more abundant during WS. Ten types of artificial containers were found with developing larvae. 70% of these habitats were located indoors. 71.42% of indoor containers were permanent and 28.58% was semi-permanent during WS. Cement tanks was the only container type permanent during DS. Ae. aegypti larval indices (CI, HI, BI) recorded were greater during WS. CONCLUSIONS Taken together, these results indicate a high risk of dengue transmission in the holy city.

Aedes Mosquito Species in Western Saudi Arabia

Abstract The Aedes Meigen (Diptera: Culicidae) mosquito species populations in the western region of Saudi Arabia, especially in and around Jeddah, are increasing, therefore increasing susceptibility of humans to the dengue virus. An extensive survey was carried out for one year, and four species were identified with the help of different pictorial keys available. The identification was based on morphological characteristics of adult female Aedes mosquitoes.

Role of climatic factors in the seasonal abundance of Aedes aegypti L. and dengue fever cases in Jeddah province of Saudi Arabia.

Fluctuation in the climatic factors influences not only the human health but also affect the abundance of disease vectors as well as infectious diseases. In the present study an attempt has been made to establish the relationship between Aedes mosquito abundance, dengue fever cases and prevailing climatic factors in the western region of Saudi Arabia. The role of Relative humidity is well established in the abundance of mosquito vector. But the role of temperature & rainfall is unpredictable in this area of study.

Effectiveness of seven mosquito larvicides against the West Nile vector Culex pipiens (L.) in Saudi Arabia

Abstract Objective To explore the effects of different chemical larvicides, bioinsecticides and insect growth regulators against the West Nile vector Culex pipiens (Diptera: Culicidae) ( Cx. pipiens ) in Saudi Arabia. Methods We tested seven commercial mosquito larvicides, including classic cyfluthrin, diazinon and propoxur, bioinsecticides Bactilarvae and Tracer 24%, and insect growth regulators Baycidal and Sumilarv. LC 50 and LC 90 values were calculated in laboratory conditions using probit analysis. Results Concerning chemical insecticides, the highest larval mortality was observed for diazinon, with LC 50 = 0.352 3 mg/L, followed by propoxur and cyfluthrin. The bacterial insecticide Tracer was more effective than Bactilarvae (LC 50 = 0.008 7 mg/L and 0.011 7 mg/L, respectively) by 1.37 folds. Furthermore, Cx. pipiens larvae were more susceptible to insect growth regulators Baycidal (IC 50 = 0.000 4 mg/L) if compared to Sumilarv (IC 50 = 0.002 9 mg/L) by 7.25 folds. Conclusions Overall, this research added basic knowledge about the effectiveness of seven mosquito larvicides with different mechanisms of action as potential candidates for the control programs of Cx. pipiens mosquito populations in Saudi Arabia.

Promoting health education and public awareness about dengue and its mosquito vector in Saudi Arabia

Currently, dengue fever is considered as the main health problem in several parts (Mekkah, Jeddah, Jazan and Najran) of Kingdom of Saudi Arabia (KSA) with dramatically increase in the number of cases reported every year. This is associated with obvious ineffectiveness in the recent control and management programs for the mosquito vector (Aedes aegypti). Here, we suggested promoting the health education and public awareness among Saudi people to improve the control of dengue mosquito vector. Several suggestions and recommendations were highlighted here to ensure effectiveness in the future control and management programs of dengue mosquito vector in KSA.

The desert wormwood (Artemisia herba-alba) – From Arabian folk medicine to a source of green and effective nanoinsecticides against mosquito vectors

The development of eco-friendly and effective insecticides is crucial for public health worldwide. Herein, we focused on the desert wormwood (Artemisia herba-alba), a plant widely used in Arabian traditional medicine, as a source of green nanoinsecticides against mosquito vectors, as well as growth inhibitors to be employed against microbial pathogens. Ag nanoparticles (AgNPs) fabricated with the A. herba-alba extract were tested on Indian and Saudi Arabian strains of Anopheles, Aedes and Culex mosquitoes. The chemical profile of the A. herba-alba extract was determined by LC-DAD-MS and 1H NMR studies. Then, AgNPs were studied using UV-vis spectroscopy, XRD, FTIR spectroscopy, TEM, and EDX analyses. Artemisia herba-alba-synthesized AgNPs showed high larvicidal toxicity against mosquitoes from both Indian and Saudi Arabian strains. LC50 of AgNPs against Indian strains was 9.76 μg/ml for An. stephensi, 10.70 μg/ml for Ae. aegypti and 11.43 μg/ml for Cx. quinquefasciatus, whereas against Saudi Arabian strains it was 33.58 μg/ml for Ae. aegypti and 38.06 μg/ml for Cx. pipiens. In adulticidal experiments, A. herba-alba extract showed LC50 ranging from 293.02 to 450 μg/ml, while AgNP LC50 ranged from 8.22 to 27.39 μg/ml. Further, low doses of the AgNPs inhibited the growth of selected microbial pathogens. Overall, A. herba-alba can be further considered as a source of phytochemicals, with special reference to saponins, for effective and prompt fabrication of AgNPs with relevant insecticidal and bactericidal activity against species of high public health importance.

Effectiveness of Slow-Release Tablet Formulations of the IGR Diflubenzuron and the Bioinsecticide Spinosad Against Larvae of Aedes aegypti (L.)

The larvicidal effectiveness of slow-release tablet formulations of the chitin synthesis inhibitor Dudim® (diflubenzuron) and the bioinsecticide Natular™ (spinosad) against mosquito larvae of Aedes aegypti (L.) has been evaluated. The results showed that the test formulations provided long-term residual control against the larvae. Effective control giving 90–100 % inhibition of adult emergence was achieved for 10 weeks post-treatment for diflubenzuron and 7 weeks for spinosad. In addition, larval treatments with slow-release diflubenzuron formulations led to a marked prolongation in the time needed for blood meal digestion and a reduction in the reproductive potential of adult survivors. On the other hand, larval treatments with slow-release formulations of spinosad tablets affect neither the time of blood meal digestion nor the reproductive capacity of mosquito adults that emerged from surviving larvae.

Effect of Temperature and Humidity on the Population Abundance of Spotted Oriental Cucumber Beetle Epilachna chrysomelina (F.) (Coccinellidae : Coleoptera) In Al - Qunfudah Western Saudi Arabia

The Melon Ladybird Beetle, Epilachna chrysomelina (Coleoptera: Coccinellidae) Fabricius, is one of the major phytophagous insects that feed on cucurbit plants. E. chrysomelina which is considered an economic pest in agriculture is a multi-habitat insect widely distributed throughout the world .It is also endemic along the Southern and the Western coast of Saudi Arabia due to the abundance of cucurbit plants (wild and domesticated) where it passes through all four developmental stages . In this research it was found that temperature and humidity affect the insect biological activities through their effect on insect reproduction and development. During some parts of the year the insect is more abundant due to the favorable conditions of temperature and humidity for reproduction. The month of March was more favorable than February while January was the least favorable.

Monitoring the population Fluctuation of the Prevalent Dipterous Fly Species Complex (Order: Diptera) by Using Malaise and Yellow Sticky Traps in Animal Pens in Jeddah Governorate, Western KSA

Published by Oriental Scientific Publishing Company