Although it has been difficult to prove the direct involvement of cockroaches (i.e. insects of the order Blattaria) in the transmission of pathogenic agents to humans, such insects often carry microorganisms that are important in nosocomial infections, and their medical importance in the spread of bacteria cannot be ruled out. In houses and institutions with poor standards of hygiene, heavy infestations with cockroaches, such as the peridomestic American cockroach (Periplaneta americana L.) and the domestic German cockroach (Blattella germanica L.), can occur. In the present study, cockroaches (126 B. germanica and 69 P. americana) were collected from four buildings (three public training hospitals and one house) in central Tehran, Iran. Each insect was processed, under sterile conditions, so that the bacteria on its external surfaces and in its alimentary tract and faecal pellets could be isolated and identified. The oldest and largest of the three hospitals sampled (a 1400-bed unit built 80 years ago) appeared to be the one most heavily infested with cockroaches, and cockroaches from this hospital accounted for most (65.4%) of the isolates of medically important bacteria made during the study. No significant difference was found between the percentages of P. americana and B. germanica carrying medically important bacteria (96.8% v. 93.6%; P>0.05). At least 25 different species of medically important bacteria were isolated and identified, and at least 22 were Gramnegative. The genus of enteric bacteria most frequently isolated from both cockroach species, at all four collection sites, was Klebsiella. The cockroaches from each hospital were much more likely to be found contaminated with medically important bacteria than those from the house. The hospital cockroaches were also more likely to be carrying medically important bacteria internally than externally (84.3% v. 64.1%; P<0.05). The implications of these and other recent results, for the control of cockroaches and nosocomial infections, are discussed.

In Iran, the prospect of malaria control relies mainly on insecticides used against the genus Anopheles (Diptera: Culicidae) as important vectors of malaria, arboviruses, and so on. Only eight out of 30 malaria mosquito vectors (Anopheles species) have been examined for insecticide resistance in Iran. This study aimed to review articles related to the incremental trend in insecticide resistance and their mechanisms among anopheline malaria vectors in Iran. A literature review was conducted based on such search engines as Iran doc, Web of Science, SID, PubMed, Scopus, and Google Scholar websites using the following keywords: “Anopheles,” “Malaria,” “Resistance,” “Vectors,” “Insecticide Resistance,” and “Iran” for data collection. Published papers in English or Persian covering 1980 to 2020 were reviewed. A total of 1125 articles were screened, only 16 of which were filtered to be pertinent in this review. While most of the mosquito vectors of malaria, such as Anopheles stephensi, were resistant to DDT, dieldrin, malathion, and becoming less susceptible to deltamethrin and other synthetic pyrethroid insecticides, few like Anopheles fluviatilis s. l. were susceptible to all insecticides. A disseminating trend in insecticide resistance among different anopheline mosquito vector species was evident. Metabolic and insecticide target-site resistance mechanisms were involved with organochlorines and pyrethroids, respectively. Insecticide resistance is becoming a severe scourge to the effectiveness of vector-borne disease management measures. This event is especially critical in developing and marginalized communities that applied chemical-based vector elimination programs for malaria; therefore, it is crucial to monitor insecticide resistance in malaria vectors in Iran using biochemical and molecular tools.

Human cutaneous leishmaniasis (CL) is of increasing public-health importance in Iran. On 10 July 2003, two mild earthquakes struck the rural town of Zarindasht in the southern Iranian province of Fars. The results of passive detection of CL cases in this town (in which patients with any skin lesions were evaluated) from April 2002 to April 2004 indicated that the earthquakes may have led to an outbreak of the disease; annual incidence increased from 58·6 detected cases/100,000 in the 12 months before the earthquakes to (an outbreak peak of) 864 detected cases/100,000 in the following 12 months. In addition, the incidence of detected CL in the town that was struck by the earthquakes in 2003 was significantly higher in the 12 months after the earthquakes than that recorded, over the same 12 months, for Fars province as a whole (P<0·05). Most (70%) of the cases detected in the town were aged ≤10 years, about half (50·4%) of the detected skin lesions were on the face, and most (89·7%) of the skin lesions were caused by Leishmania major. Incidence over the study period showed marked seasonality, with most (79·5%) of the detected cases occurring between November and February. In areas where the disease is endemic, CL may need to be considered among the health threats posed by natural disasters such as earthquakes, and increased surveillance for CL after future earthquakes may be justified.

To investigate the prevalence of fecundity and other reproductive problems among a group of farmers in Kavar district of Fars province, southern Iran. A total of 268 randomly selected married male farm workers were investigated. A questionnaire was devised and validated [Cronbach's α-coefficient (0.81)]. Subjects were directly interviewed and the questionnaire forms were completed for them. The prevalence of current primary infertility among the studied population was about 7.4% (P=0.001). Similarly, 6.3% of farm workers had offsprings with congenital malformations. Finally, 1.5% and 9% of farmers' wives had a history of stillbirth and abortion, respectively. It was concluded that the prevalence of current primary infertility were higher among farm workers families than in the normal population (P<0.05). Additionally, stillbirth and spontaneous abortion were more common in the wives of farm workers than in the normal population, although the difference did not reach statistical significance. These effects are likely to be attributed to the exposure of farm workers to pesticides.

Although house flies (Musca domestica) do not directly cause disease in humans, they transmit pathogens to them, which provide the basis for many diseases. The main way to deal with this insect is to use insecticides. Due to the resistance from insecticides, the fight against house flies has been hampered. This study aimed to determine the prevalence of knockdown resistance against organochlorine insecticides in house flies worldwide. This study was conducted via a systematic review and meta-analysis to investigate the prevalence of knockdown resistance against organochlorine insecticides in house flies. Accordingly, by searching the databases of Web of Science, PubMed, Scopus, Proquest, Bioone, and Embase, all published articles were extracted, and reviewed until the end of May 2022. Statistical data analysis was performed using the random-effects model in the meta-analysis, meta-regression, and I² index. Nine studies entered the meta-analysis process. Based on this, the prevalence of knockdown resistance against organochlorine insecticide in house flies was estimated to be 49.1%. Meta-regression showed that the prevalence of knockdown resistance increased with increasing years of study but decreased with increasing sample size. According to the findings, about 50% of house flies have knockdown resistance against organochlorine insecticide. As a result, it is necessary to adopt effective and combined methods to combat this insect to control it and prevent the transmission of diseases caused by it.