Journal of Arthropod-Borne Diseases
Volume:15 Issue: 4, Dec 2021

Culex pipiens complex is considered as a vector of some important diseases suchas West Nile fever, equine encephalitis, Rift valley fever, St. Louis encephalitis, Elephanthiasis and avian malaria in the world. The main measure for vector control is using insecticides. High use of insecticides caused resistance in the populations. The aim of this study was to review the status of insecticide resistance in the vector.

Insecticide resistance in this species was found by the available papers and map of the data for carbamates, organochlorine, organophosphates, pyrethroids, microbial and insect growth regulator insecticides were done. An intensive search of scientific literature was done in “PubMed”, “Web of Knowledge”, “Scopus”, “Google Scholar”, “SID”, and related resources.

Results showed that a wide variety of resistance to different insecticides in the country. Due to importance of this species in transmission of diseases.

resistance management strategies should be further considered to prevent from in secticide resistance and replacement of novel approach for vector control.

Due to the confirmation of the presence of the novel coronavirus in the feces and municipal sewerage system, and the feeding of domestic insects from fecal matter, as well as the ability of these insects to mechanically transmit microbes from the sewerage system. This study was aimed at molecular evaluation of the novel coronavirus infection isolated on cockroaches and flies collected from Kamkar-Arabnia Hospital in Qom City, Iran.

Totally, 18 samples; (12 samples cockroaches and 6 flies) from the external surface of cockroaches and houseflies as well as their digestive system were prepared. After designed and synthetized exogenous heterologous internal control, the RNA was extracted to investigate the contamination of these samples with the novel coronavirus. To detect the virus, the E and RdRp genes were identified.

Investigation of coronavirus E gene using the multiplex one-step qPCR technique on the collected samples showed an amplification plot in CT= 35.70 related to the internal surfaces of cockroaches collected from the treatment and sick room of the hospital. Also, the design of internal control to ensure the accuracy of the extraction process was successful.

According to the findings of the present study regarding detecting the presence of the coronavirus infection in the digestive system of domestic insects such as American cockroaches and considering their ability to mechanically transmit viruses, it is recommended to control the domestic insects that are in close contact with humans in crowded places such as hospitals and health centers during the Covid-19 pandemic.

Among neglected zoonotic diseases, leishmaniases caused by Leishmania parasite through infected female sand fly bite, are a group of diseases found in 98 countries and territories representing a critical burden of disease worldwide. Vector management plays a crucial role in reducing the burden of vector-borne diseases by WHO’s global plan. The objective of the current study was to assess the susceptibility status of wild phlebotomine sand flies from Esfahan Province, central Iran, to the recommended insecticides by WHO.

Sand flies were collected by mouth aspirator in Matin Abad desert Eco-resort and were tested using WHO adult mosquito test kit against Dichlorodiphenyltrichloroethane (DDT) 4%, Deltamethrin 0.05%, Malathion 5% and Propoxur 0.1%. The number of knockdown sand flies were recorded during exposure time in ten minutes interval for DDT and Deltamethrin and they were allowed to recover for 24 hours. Knockdown Time50 (KD50) and KD90 were generated for them using Probit software. They were mounted and identified by valid keys.

Among the tested insecticides against female Phlebotomus papatasi, DDT, Deltamethrin, and Malathion recorded the highest mortality rate of 100%, followed by Propoxur with 92.2% mortality for a one-hour exposure. For DDT, KD50 and KD90 were calculated 21.87 and 42.93 and for Deltamethrin, they were 23.74 and 56.50 minutes respectively. Total sand flies exposed with DDT  and Deltamethrin shed their leg(s).

It is concluded that Ph. papatasi from central Iran is susceptible to DDT, Deltamethrin, Malathion, and Propoxur.

Objectives :

Due to undesired environmental impact of insecticides as well as resistant of vectors to them, development of organic and natural insecticides have been more considered. In the current study, we developed nanoemulsion of eucalyptus and investigated lavicidal activity of it against malaria vector, Anopheles stephensi and Culex pipiens under  laboratory as well as semi field conditions. 

An optimized nanoemulsion was prepared by mixing Eucalyptus oil, Tween 80 and ethanol at ratio of 1:2:1.5 in distilled water, then, stirred for 20 minute at room temperature. The product was then used for bioassay tests against 3-4th instar larvae of Anopheles stephensi as well as Culex pipiens.  Furthermore, semi field trial was carried out to evaluate larvicidal activity of nanoemulsion of eucalyptus.

Nanoemulsion of eucalyptus showed significantly high lavicidal activity comparing with bulk eucalyptus essential oil. The LC50 and LC90 value of nanoemulsion against An. stephensi were 111.0 and 180.8 ppm respectively and 29.5 and 73.7 ppm for Cx.  pipiens, respectively. In the semi field condition, the Nanoemulsion of eucalyptus decreased 1-2nd instar larval density of Culicines and Anophelines to 90.1%  and 85.2%, respectively.

The nano formulation of eucalyptus oil showed high larvicidal activity.  Therefore, nanoemulsion of eucalyptus oil can be used as an eco-friendly larvicide against mosquitoes.

Out of 931 species of ticks, Rhipicephalus microplus is the most widely studied tick species due to its pivotal role in transmission of babesiosis and anaplasmosis, resulting in huge economic loss in cattle and buffalo’s industry. Chemical control using deltamethrin forms the mainstay of tick control strategy because of high potency and low toxicity. However, inadvertent use of deltamethrin has led to the development of deltamethrin resistance in field ticks

The engorged female ticks were collected in a plastic container covered with a cotton plug from 10 places (Jarwa, Barwa, Khajakhera, Banisi, Nakipur, Dhangar, Badopal, Shivalya Dharamshala, Siwani and Meham) of five districts of western Haryana. The Larval Packet Test (LPT) was conducted for the characterization of resistance in field tick.

In the present study, ticks were collected from 10 places from 5 districts of western Haryana and evaluated against deltamethrin using larval packed test. The LC50 values (confidence interval) of ticks larvae against deltamethrin collected from Nakipur, Dhangar, Barwa, Badopal, Shivalya Dharamshala, Siwani, Jarwa, Khajakhera, Meham and Banisi are 73.6 (67.2–81.9), 61.2 (61.6–98.5), 52.7 (14.4–101.0), 140.0 (86.7–448.6), 65.8 (37.1–95.2), 232.1 (201.0–304.7), 3.72 (0.20–9.87), 21.3 (12.0–31.6), 107.6 (96.8–127.6), 54.2 (43.4–58.4) ppm, respectively. The resistance factor ranges from 0.31 to 11.86, indicating variable resistance among field isolates.

Data generated on deltamethrin resistance status in R. microplus from Haryana, India can be used as an indicator for the management of the species in the state.

Fauna and larval habitat characteristics studies on mosquitoes are important tools to identify the breeding places of the vectors and management of the control strategies. This study was done to provide data on Culicidae fauna, larval habitat characteristics and identifying potential vectors of West Nile virus in Lorestan Province, west of Iran.

Culicidae mosquitoes were collected at three counties and nine site stations from Lorestan Province, west of Iran in 2017. Adult mosquitoes were collected using human and animal bite collection methods, New Jersey and CDC light traps and pit shelters by aspirator. Larva were collected by dipping method. RT-PCR technique was employed for detection of the West Nile virus among mosquito’s samples.

4805 mosquitoes were collected from three counties and nine sites in Lorestan Province during June–October 2017, including 4363 adults and 442 larvae. The most abundant species collected from all counties in both adult and larval stages were Culex pipiens (49.10%), Cx. theileri (31.82%), Anopheles maculipennis (11.09%), An. superpictus (2.66%), An. stephensi (2.12%), Cx. perexiguus (1.89%), An. dthali (1.17%) and An. sacharovi (0.15%) respectively. West Nile virus was detected in none of mosquitoes examined.

The results of this study revealed that arbovirus vectors such as Cx. pipiens along  with Cx. theileri and Cx. perexiguus are well adapted to a broad range of habitats and different climatic conditions in Lorestan Province. That necessitates further routine surveillance of arboviral infections.

Culex pipiens has a significant public health importance since it is an important vector of West Nile virus and Rift Valley fever virus. We, therefore, aimed to determine the insecticide resistance level in Cx. pipiens populations in the Aegean and Mediterranean regions of Turkey.

Bioassays have been carried out against Dichlorodiphenyltrichloroethane (DDT) (4%), Malathion (5%), Fenitrothion (1%), Propoxur (0.1%), Bendiocarb (0.1%), Permethrin (0.75%) and Deltamethrin (0.05%). Biochemical analyses have been performed to detect non-specific esterase, mixed function oxidase, glutathione-s-transferase and acetylcholinesterase levels. A knockdown resistance (kdr) (L1014F) and Acetylcholinesterase (Ace-1) (G119S) mutations have been detected by using allele-specific primers and a polymerase chain reaction (PCR) amplification of specific alleles (PASA) diagnostic test was performed for detection of F290V mutation.

Bioassay results showed that all Cx. pipiens populations were resistant to DDT, Malathion, Fenitrothion, Bendiocarb, Propoxur and some of the populations have started to gain Permethrin and Deltamethrin resistance. Biochemical analyses results revealed that altered glutathione-s-transferases, P450 monooxygenases, esterase levels might be responsible for DDT, organophosphate, carbamate and pyrethroid resistance in Cx. pipiens populations. Results showed mild to high frequency of L1014F, low frequency of F290V but no Ace-1 G119S mutation within the populations. Additionally, acetylcholinesterase insensitivity was not significantly high within the most of these populations.

Overall results may help to fulfil the lacking information in the literature regarding insecticide resistance status and underlying mechanism of Culex pipiens populations of the Mediterranean and Aegean region of Turkey by using all bioassays, molecular tests and biochemical assays.

SScabies is caused by the parasite Sarcoptes scabiei. The disease was first described in ancient Greece, while Ferdinand Von Hebra described the stages of development of the arthropodite from the egg to larvae and the adult form of sarcoptosis. The final stage is characterized by the travel of the female parasite and the laying of eggs in stratum corneum and followed by the death of the causer. The main characteristic symptom of scabies is relentless pruritus which is a result of such an infestation inside the skin, as the body reacts to parasites and their excretions, where mites burrow and lay eggs.

Here we present the 85-year-old patient with scabies crustosa, latent diabetes and renal insufficiency.

Persistent pruritus and scabies rash, where large numbers of mites were detected, was left untreated and further progressed into sores due to scratching. Weakened immunity and chronic illness in the patient resulted in a more severe form of the disease which was diagnosed as scabies crustosa. After treatment with a supplemented antiscabiotic regimen, the patient remained symptom free.

Large population movements, one of the main factors of spread and frequent incidence of scabies, contact with the sick, hygiene means, exchange of wardrobes, sharing bed with the sick, schools, preschools, old-age-care institutions and hospitals, enable spread of the disease. In addition, severe types of scabies that form thick crusts on the skin and present with pruritus as a symptom should be considered in immunocompromised and elderly patients with renal insufficiency where pruritus is also prevalent.