Insect Repellants During Pregnancy in the Era of the Zika Virus

Do we protect ourselves against West Nile Virus? A systematic review on knowledge, attitudes, and practices and their determinants

BACKGROUND

West Nile virus (WNV) is a mosquito-borne flavivirus. In humans, 80% of infections are asymptomatic, while approximately 20% experience influenza-like symptoms. Fewer than 1% develop the neuroinvasive form which can lead to encephalitis, meningitis, acute flaccid paralysis, and even death. The global spread of the virus to areas where it was not previously present has become a growing concern. Since the 2000 s, there have been numerous outbreaks affecting local and travelling populations worldwide. Given the lack of a vaccine, preventative measures are primarily focused on surveillance, vector control, and the use of personal protective behaviours (PPBs). The importance of PPBs is central to public health recommendations. However, translating these messages into coherent action by the public can prove challenging, as the uptake of such measures is inevitably influenced by socio-economic factors, awareness, knowledge, and risk perception.

METHODS

A PRISMA-based systematic research was conducted on EMBASE, PubMed/MEDLINE, and Web of Science databases. PROSPERO registration number CRD42023459714. Quality of studies included in the final stage was evaluated using the Critical Appraisal Checklist for Cross-Sectional Study (CEBMa).

RESULTS

2963 articles were screened, and 17 studies were included in the final round. Out of these, six were deemed of high quality, ten were of medium quality, and one was of low quality. In almost all studies considered, both awareness and knowledge of WNV transmission were above 90%, while concern about WNV ranged from 50% to 80%. Concern about the safety of repellents, either with or without DEET, ranged from 27% to 70%. The percentage of people actually using repellents ranged from 30% to 75%, with the lowest usage reported among individuals over 60 years old (29%) and pregnant women (33%), and the highest among students aged 9-11 (75%). Concern for West Nile Virus (WNV) was consistently linked to an increase in taking preventative measures, including the use of repellents, by two to four times across studies. The school-based intervention was effective in increasing the practice of removing standing water (AOR=4.6; 2.7-8.0) and wearing long clothing (AOR=2.4; 95%CI: 1.3-4.3), but did not have a significant impact on the use of repellents.

CONCLUSIONS

The present systematic review provides an overview of the knowledge, attitudes, and practices (KAP) of WNV and their determinants. While concern about West Nile Virus (WNV) and its effects can be a significant motivator, it is important to promote evidence-based personal protective behaviours (PPBs) to counter unwarranted fears. For example, the use of repellents among the most vulnerable age groups. Given the geographical expansion of WNV, it is necessary to target the entire population preventively, including those who are difficult to reach and areas not yet endemic. The findings of this investigation could have significant implications for public health and support well-informed and effective communication strategies and interventions.

In Vitro Effects of Cypermethrin and Glyphosate on LPS-Induced Immune Cell Activation

(1) Background: The insecticide cypermethrin (Cypm) and the herbicide glyphosate (Glyp) are among the most widely used pesticides. While the two pesticides have been considered to have low toxicity in mammals, some indication of potential immunotoxicity has emerged. The aim of this work was to investigate in vitro the effects of Cypm and Glyp on bacteria lipopolysaccharide (LPS)-induced immune cell activation and of Cypm on 2-mercaptobenzothiazole (MBT)-induced maturation of dendritic cells (DCs). (2) Methods: The release of the inflammatory cytokines TNF-α and IL-8, the expression of the surface markers CD54 and CD86 in human primary peripheral blood mononuclear cells (PBMC), and THP-1 cells were investigated together with CD83, HLA-DR, IL-6, and IL-18 in DCs. (3) Results: While no significant modulation on LPS-induced immune cell activation was observed following Glyp exposure, with only a trend toward an increase at the highest concentration tested, Cypm reduced the responses to LPS and to MBT, supporting a direct immunosuppressive effect. Overall, the present study contributes to our understanding of pesticide-induced immunotoxicity, and the results obtained support evidence showing the immunosuppressive effects of Cypm.

Vector-borne disease, climate change and perinatal health

Vector-borne diseases (VBDs) are caused by infectious pathogens that spread from an infected human or animal reservoir to an uninfected human via a vector (mosquito, tick, rodent, others) and remain an important cause of morbidity and mortality worldwide. Pregnant individuals and their fetuses are especially at risk, as certain pathogens, such as Zika virus, have specific implications in pregnancy and for neonatal health. Global climate change is affecting the incidence and geographic spread of many VBDs. Thus, it is important for clinicians in the fields of obstetrics/gynecology and newborn medicine, regardless of geographic location, to familiarize themselves with a basic understanding of these conditions and how climate change is altering their distributions. In this chapter, we review the incidence, clinical presentation, implications during pregnancy and intersection with climate change for four of the most important VBDs in pregnancy: malaria, Zika, dengue and Chagas disease. Although not exhaustive of all VBDs, a more extensive table is included for reference, and our discussion provides a helpful framework for understanding other vector-borne pathogens and perinatal health.

Arboviral vaccines for use in pregnant travelers

Pregnant women traveling abroad can be exposed to a variety of arboviruses, primarily spread by mosquitoes or ticks. Some arboviral infections can be of particular concern for pregnant women or their fetuses. Vaccination is one preventive measure that can reduce the risk for infection. Several arboviral vaccines have been licensed for many years and can be used to prevent infection in travelers, namely Japanese encephalitis, yellow fever, and tick-borne encephalitis vaccines. Recommendations on use of these vaccines in pregnancy vary. Other arboviral vaccines have been licensed but are not indicated for use in pregnant travelers (e.g., dengue vaccines) or are in development (e.g., chikungunya, Zika vaccines). This review describes arboviral vaccines for travelers, focusing on women who are pregnant and those planning travel during pregnancy.

Insect repellents: An updated review for the clinician

Malaria, Zika virus, West Nile virus, Dengue fever, and Lyme disease are common causes of morbidity and mortality around the world. While arthropod bites may cause local inflammation and discomfort, a greater concern is the potential to develop deadly systemic infection. The use of insect repellents (IRs) to prevent systemic infections constitutes a fundamental public health effort. Cost effectiveness, availability, and high efficacy against arthropod vectors are key characteristics of an ideal IR. Currently, numerous IRs are available on the market, with N,N-diethyl-3-methylbenzamide (DEET) being the most widely used. DEET has an excellent safety profile and remarkable protection against mosquitoes and various other arthropods. Other Environmental Protection Agency-registered IR ingredients (eg, permethrin, picaridin, IR3535, oil of lemon eucalyptus, oil of citronella, catnip oil, and 2-undecanone) are alternative IRs of great interest because some of these ingredients have efficacies comparable to that of DEET. These alternative IRs possess low toxicity and favorable customer experiences in use (eg, cosmetically pleasant, naturally occurring). This review summarizes the currently available Environmental Protection Agency-registered IRs, including their origins, mechanisms of action, side effect profiles, and available formulations. This review will enable the clinician to select the best IR option to meet a patient's needs and provide the greatest protection from arthropod bites and their sequelae.

Simultaneous exposure to both Zika virus and household insecticides during pregnancy, and fetal growth and infant developmental behavior outcomes at 18 months, in Guadeloupe

BACKGROUND

Perinatal infection with Zika virus (ZIKV) could result in adverse growth, developmental and behavioral outcomes, while insecticides used to control mosquitoes are neurotoxic.

OBJECTIVES

We aim to study the role played by exposure during pregnancy to both ZIKV and household insecticides in newborn health, development and behavior at age of 18 months.

METHODS

Maternal and cord blood samples from a cohort of pregnant women (created during Guadeloupe's Zika epidemic of 2016) were used to identify ZIKV infection during pregnancy. A self-administered questionnaire at birth documented prenatal household use of insecticides. Birth weight and head circumference were collected from maternity records (n = 708). Infant development and behaviors were documented at 18 months of age through the Ages and Stages Questionnaire and the Quebec Longitudinal Study of Child Development (n = 409). Logistic and linear regression models were performed, taking into account confounding factors.

RESULTS

Use of household insecticides was associated with smaller head circumference and lower birth weight among newborns from mothers not exposed to ZIKV: 0.3 cm (95% CI: 0.6, 0) and -82 g (95% CI: 165, 0), respectively. Similar decreases were observed with ZIKV exposure among mothers not reporting household insecticides use, and with presence of both exposures. The combined presence of ZIKV exposure and insecticide use was associated with lower ASQ fine motor scores (-3.9; 95% CI: 7.3, -0.4), and higher hyperactivity scores (0.8; 95% CI: 0.0, 1.5), compared to no exposure to either. A higher opposition score was observed in association with ZIKV exposure among non-users of insecticide (0.6; 95% CI: 0.0, 1.2).

CONCLUSION

Adverse neurodevelopmental outcomes at 18 months of age were observed with prenatal ZIKV exposure, and with higher magnitude when mothers reported use of household insecticides. At birth, rates of adverse fetal growth were however similar for the combined presence of exposure and either of the exposures.

Advances and future prospects of pyrethroids: Toxicity and microbial degradation

Pyrethroids are a class of insecticides structurally similar to that of natural pyrethrins. The application of pyrethrins in agriculture and pest control lead to many kinds of environmental pollution affecting human health and loss of soil microbial population that affect soil fertility and health. Natural pyrethrins have been used since ancient times as insect repellers, and their synthetic versions especially type 2 pyrethroids could be highly toxic to humans. PBO (Piperonyl butoxide) is known to enhance the toxicity of prallethrin in humans due to the resistance in its metabolic degradation. Pyrethroids are also known to cause plasma biochemical profile changes in humans and they also lead to the production of high levels of reactive oxygen species. Further they are also known to increase SGPT activity in humans. Due to the toxicity of pyrethrins in water bodies, soils, and food products, there is an urgent need to develop sustainable approaches to reduce their levels in the respective fields, which are eco-friendly, economically viable, and socially acceptable for on-site remediation. Keeping this in view, an attempt has been made to analyse the advances and prospects in using pyrethrins and possible technologies to control their harmful effects. The pyrethroid types, composition and biochemistry of necessary pyrethroid insecticides have been discussed in detail, in the research paper, along with their effect on insects and humans. It also covers the impact of pyrethroids on different plants and soil microbial flora. The second part deals with the microbial degradation of the pyrethroids through different modes, i.e., bioaugmentation and biostimulation. Many microbes such as Acremonium, Aspergillus, Microsphaeropsis, Westerdykella, Pseudomonas, Staphylococcus have been used in the individual form for the degradation of pyrethroids, while some of them such as Bacillus are even used in the form of consortia.

Vector control strategies in Brazil: a qualitative investigation into community knowledge, attitudes and perceptions following the 2015-2016 Zika virus epidemic

OBJECTIVE

The World Health Organization declared a Public Health Emergency of International Concern following the rapid emergence of neonatal microcephaly in Brazil during the 2015-2016 Zika virus (ZIKV) epidemic. In response, a national campaign sought to control Aedes mosquito populations and reduce ZIKV transmission. Achieving adherence to vector control or mosquito-bite reduction behaviours, including the use of topical mosquito repellents, is challenging. Coproduction of research at the community level is needed to understand and mitigate social determinants of lower engagement with Aedes preventive measures, particularly within disempowered groups.

DESIGN

In 2017, the Zika Preparedness Latin America Network (ZikaPLAN) conducted a qualitative study to understand individual and community level experiences of ZIKV and other mosquito-borne disease outbreaks. Presented here is a thematic analysis of 33 transcripts from community focus groups and semistructured interviews, applying the Health Belief Model (HBM) to elaborate knowledge, attitudes and perceptions of ZIKV and vector control strategies.

PARTICIPANTS

120 purposively sampled adults of approximate reproductive age (18-45); 103 women participated in focus groups and 17 men in semistructured interviews.

SETTING

Two sociopolitically and epidemiologically distinct cities in Brazil: Jundiaí (57 km north of São Paolo) and Salvador (Bahia state capital).

RESULTS

Four key and 12 major themes emerged from the analysis: (1) knowledge and cues to action; (2) attitudes and normative beliefs (perceived threat, barriers, benefits and self-efficacy); (3) behaviour change (household prevention and community participation); and (4) community preferences for novel repellent tools, vector control strategies and ZIKV messaging.

CONCLUSIONS

Common barriers to repellent adherence were accessibility, appearance and effectiveness. A strong case is made for the transferability of the HBM to inform epidemic preparedness for mosquito-borne disease outbreaks at the community level. Nationally, a health campaign targeting men is recommended, in addition to local mobilisation of funding to strengthen surveillance, risk communication and community engagement.

Zika virus infection in pregnant women and their children: A review

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) transmitted primarily by Aedes mosquitoes. ZIKV can be transmitted to humans by non-vector borne mechanisms such as sexual intercourse, maternal-foetal transmission or blood transfusion. In 2015, ZIKV emerged in the Americas, and spread to 87 countries and territories with autochthonous transmission, distributed across four of the six WHO regions. Most ZIKV infections in pregnancy are asymptomatic, but mother to child transmission of the virus can occur in 20 to 30% of cases and cause severe foetal and child defects. Children exposed to ZIKV while in utero might develop a pattern of structural anomalies and functional disabilities secondary to central nervous system damage, known as congenital Zika syndrome, and whose most common clinical feature is microcephaly. Normocephalic children born to mothers with ZIKV infection in pregnancy, and with no observable Zika-associated birth defects, may also present with later neurodevelopmental delay or post-natal microcephaly. Screening and detection of ZIKV infection in pregnancy is essential, because most women with ZIKV infection are asymptomatic and clinical manifestations are non-specific. However, the diagnosis of ZIKV infection poses multiple challenges due to limited resources and scarce laboratory capabilities in most affected areas, the narrow window of time that the virus persists in the bloodstream, the large proportion of asymptomatic infections, and the cross-reactivity with other flaviviruses such as Dengue virus (DENV). Molecular methods (RT-PCR) are the most reliable tool to confirm ZIKV infection, as serodiagnosis requires confirmation with neutralization tests in case of inconclusive or positive serology results. Prenatal ultrasound assessment is essential for monitoring foetal development and early detection of possible severe anomalies. A mid- and long-term follow-up of children exposed to ZIKV while in utero is necessary to promptly detect clinical manifestations of possible neurological impairment. Tweetable abstract: Zika virus infection during pregnancy is a cause of pregnancy loss and disability in children. Protection against mosquito bites, access to sexual and reproductive health services, prompt screening and detection of ZIKV infection in pregnancy, and prenatal ultrasound monitoring are key control strategies whilst a vaccine is not available.

Knowledge, attitudes, and practices regarding vector-borne diseases in central Mexico

BACKGROUND

While vector-borne diseases (VBDs) pose an important public health problem worldwide, there is a limited and conflicting knowledge about such illnesses in rural or urban settings. The present study aimed to explore the social representations (SRs) held by people in the state of Puebla, Mexico on insects and the diseases they transmit. Understood as the group of ideas held and shared by a group of human beings which enable them to understand and interpret the world, SRs constitute what could be called a collective science or knowledge of everyday life.

METHODS

The present study was conducted in six municipalities in the state of Puebla, wherein an open-ended questionnaire was applied with three age ranges. A total of 360 questionnaires were applied with people dedicated to a variety of activities. The survey data was analyzed to identify the SR's structure (the central nucleus of the SR and its peripheral system) and the level of organization in order to explore the degree to which the ideas that constitute it are shared and based on consensus. To describe the structure of the SR, a network analysis was conducted and complemented by a correspondence analysis, which also enables the differences between social groups to be identified.

RESULTS

Popular knowledge on insects and VBDs is often limited, even in communities in which more than one-vector insect is found. The elements that were most frequently mentioned in the data, as pertaining to the insect-disease relationship, were mosquitoes and dengue fever, with scorpions (which are arachnids and not insects) receiving the second-highest number of mentions, while other insects such as kissing bugs, flies, and cockroaches were also mentioned as transmitting VBDs. While television was the main information source on VBDs for the residents of these communities, biology books were also mentioned. Chemical control measures (insect repellents) were the most used prevention method, and traditional medicine was the remedy most commonly used to treat insect bites and transmitted diseases. Entomophobia was the main cause for the respondents' fear and rejection of insects. Beyond the deleterious effects of many insects, those surveyed also recognized a positive relationship with insects due to economic and nutritional benefits they provide.

CONCLUSIONS

The present study provides relevant information on how insects and the diseases they transmit are perceived by rural and urban communities. Although the population is aware of dengue fever and the role of mosquitoes in transmitting it, information campaigns are required for other historically neglected VBDs, such as leishmaniasis, Chagas disease, and, even, rickettsiosis. As it is important to understand the impact that these illnesses have on communities further research is required to ensure that better information and guidance is provided on VBDs in order to develop a culture of illness prevention in not only the rural but also the metropolitan communities of the state of Puebla.

Pyrethroids: How They Affect Human and Animal Health?

Pyrethroids are pesticides commonly used in crop protection; in the forestry, wood, and textile industries; as well as in medicine and veterinary medicine to treat parasitic crustacean infestations. They have been found to be relatively safe for humans and animals. Pyrethroids are recommended for personal protection against malaria and virus Zika by the World Health Organization. Pyrethroids act on voltage-gated sodium channels, which cause an influx of sodium ions into the nerve cells and permanent depolarization. They also influence activities of enzymes, especially in nerve and liver cells. Contact of pyrethroids with the skin, digestive tract, and respiratory tract results in their penetration into the body. Due to the importance of the subject, a summary of the current state of knowledge on the toxic effects of pyrethroids was presented in the comprehensive review by Chrustek et al, published in journal Medicina. Particular attention was paid to nephrotoxic, hepatotoxic, cardiotoxic, immunotoxic, neurotoxic, and behavioral effects of pyrethroids on human and animal bodies. It could be added that pyrethroids generate oxidative stress, which modifies DNA, RNA, protein, lipid and carbohydrate molecules. However, public awareness of the possible negative effects of the use of insecticides is still low. Further research should be carried out to clarify the molecular basis of the pathomechanism of pyrethroid detrimental action. Proper dissemination of the results seems to be of first importance for public health.

Malaria in the pregnant traveler

Pregnant travelers face numerous risks, notably increased susceptibility to or severity of multiple infections, including malaria. Because pregnant women residing in areas non-endemic for malaria are unlikely to have protective immunity, travel to endemic areas poses risk of severe illness and pregnancy complications, such as low birthweight and fetal loss. If travel to malaria-endemic areas cannot be avoided, preventive measures are critical. However, malaria chemoprophylaxis in pregnancy can be challenging, since commonly used regimens have varying levels of safety data and national guidelines differ. Furthermore, although chloroquine and mefloquine have wide acceptance for use in pregnancy, regional malaria resistance and non-pregnancy contraindications limit their use. Mosquito repellents, including N,N-diethyl-m-toluamide (DEET) and permethrin treatment of clothing, are considered safe in pregnancy and important to prevent malaria as well as other arthropod-borne infections such as Zika virus infection. Pregnant travelers at risk for malaria exposure should be advised to seek medical attention immediately if any symptoms of illness, particularly fever, develop.

Prenatal exposure to pesticides and risk for holoprosencephaly: a case-control study

BACKGROUND

Pesticide exposure during susceptible windows and at certain doses are linked to numerous birth defects. Early experimental evidence suggests an association between active ingredients in pesticides and holoprosencephaly (HPE), the most common malformation of the forebrain in humans (1 in 250 embryos). No human studies to date have examined the association. This study investigated pesticides during multiple windows of exposure and fetal risk for HPE. It is hypothesized that pre-conception and early pregnancy, the time of brain development in utero, are the most critical windows of exposure.

METHODS

A questionnaire was developed for this retrospective case-control study to estimate household, occupational, and environmental pesticide exposures. Four windows of exposure were considered: preconception, early, mid and late pregnancy. Cases were identified through the National Human Genome Research Institute's ongoing clinical studies of HPE. Similarly, controls were identified as children with Williams-Beuren syndrome, a genetic syndrome also characterized by congenital malformations, but etiologically unrelated to HPE. We assessed for differences in odds of exposures to pesticides between cases and controls.

RESULTS

Findings from 91 cases and 56 controls showed an increased risk for HPE with reports of maternal exposure during pregnancy to select pesticides including personal insect repellants (adjusted odds ratio (aOR) 2.89, confidence interval (CI): 0.96-9.50) and insecticides and acaricides for pets (aOR 3.84, CI:1.04-16.32). Exposure to household pest control products during the preconception period or during pregnancy was associated with increased risk for HPE (aOR 2.60, OR: 0.84-8.68). No associations were found for occupational exposures to pesticides during pregnancy (aOR: 1.15, CI: 0.11-11.42), although exposure rates were low. Higher likelihood for HPE was also observed with residency next to an agricultural field (aOR 3.24, CI: 0.94-12.31).

CONCLUSIONS

Observational findings are consistent with experimental evidence and suggest that exposure to personal, household, and agricultural pesticides during pregnancy may increase risk for HPE. Further investigations of gene by environment interactions are warranted.

Management of Patients in the Context of Zika Virus: ACOG COMMITTEE OPINION, Number 784

Zika virus is a flavivirus with the potential to cause serious adverse pregnancy and infant outcomes. Although rates of Zika virus infection have decreased in the United States, obstetrician-gynecologists and other health care providers should continue to assess their patients for potential exposure based on travel or sexual history and test symptomatic patients with possible exposure and pregnant women with ongoing exposure regardless of symptoms in accordance with the Centers for Disease Control and Prevention recommendations. Pregnant women and those planning a pregnancy should talk to their health care providers about potential risks before traveling to an area where current or past Zika virus transmission has occurred. Testing recommendations for pregnant women with possible Zika virus exposure differ based on the presence or absence of symptoms of Zika virus infection and the circumstances of possible exposure. If obstetrician-gynecologists or other health care providers identify a patient who has possibly been exposed to the Zika virus and may require testing, they should contact their local or state health department for assistance. Consultation with a maternal-fetal medicine specialist or an infectious disease specialist with expertise in the management of infectious diseases in pregnancy may be useful for pregnant women with possible maternal Zika virus infection or concerning fetal findings. Zika virus identification and follow-up care of infants born to women with possible exposure to Zika virus during pregnancy are critical and can ensure that appropriate intervention services are available to affected infants. Obstetrician-gynecologists and other obstetric care providers should have a system to ensure relevant information regarding a woman's Zika infection status is communicated to pediatric care providers.

Association Between Exposure to Pyrethroid Insecticides and Risk of All-Cause and Cause-Specific Mortality in the General US Adult Population

IMPORTANCE

Widespread exposure to pyrethroid insecticides has been reported among the general population in the United States and worldwide. However, little is known about the association of pyrethroid exposure with long-term health outcomes in adults.

OBJECTIVE

To examine the association of pyrethroid exposure with all-cause and cause-specific mortality among adults in the United States.

DESIGN, SETTING, AND PARTICIPANTS

The nationally representative cohort included 2116 adults aged 20 years and older who participated in the US National Health and Nutrition Examination Survey conducted from 1999 to 2002 and provided urine samples for pyrethroid metabolite measurements. Participants were linked to mortality data from the survey date through December 31, 2015. Data were analyzed from May to August 2019.

EXPOSURES

Urinary levels of 3-phenoxybenzoic acid, a general pyrethroid metabolite and commonly used biomarker for pyrethroid exposure, were determined by using high-performance liquid chromatography coupled with electrospray chemical ionization and tandem mass spectrometry.

MAIN OUTCOMES AND MEASURES

Mortality from all causes, cardiovascular disease, and cancer.

RESULTS

This cohort study of 2116 adults comprised 1145 women (weighted proportion, 51.6%) and 971 men (weighted, 48.4%), with a weighted mean (SE) age of 42.6 (0.5) years; 958 participants (weighted, 68.4%) were of non-Hispanic white ancestry, 646 (weighted, 14.7%) of Hispanic ancestry, 419 (weighted, 11.3%) of non-Hispanic black ancestry, and 93 (weighted, 5.6%) of other ancestry. During a median of 14.4 years (range, 0.1-16.8 years) of observation, 246 deaths occurred, including 41 associated with cardiovascular disease and 52 associated with cancer. Participants with higher urinary 3-phenoxybenzoic acid levels were at a higher risk of death during the follow-up period, with death occurring in 8.5% (unweighted, 75 of 709), 10.2% (unweighted, 81 of 701), and 11.9% (unweighted, 90 of 706) of participants across increasing tertiles of urinary 3-phenoxybenzoic acid levels. After adjustment for age, sex, race/ethnicity, socioeconomic status, dietary and lifestyle factors, body mass index, and urinary creatinine levels, the hazard ratios for all-cause mortality, cardiovascular disease mortality, and cancer mortality among participants with the highest tertile compared with those with the lowest tertile of urinary 3-phenoxybenzoic acid levels were 1.56 (95% CI, 1.08-2.26), 3.00 (95% CI, 1.02-8.80), and 0.91 (95% CI, 0.31-2.72), respectively.

CONCLUSIONS AND RELEVANCE

In this nationally representative sample of US adults, environmental exposure to pyrethroid insecticides was associated with an increased risk of all-cause and cardiovascular disease mortality. Further studies are needed to replicate the findings and determine the underlying mechanisms.

An investigation into the knowledge, perceptions and role of personal protective technologies in Zika prevention in Colombia

Background

Arboviruses transmitted by day-biting Aedes mosquitoes are a major public health concern. With the challenges inherent in arbovirus vaccine and therapeutics development, vector control and bite prevention strategies are among the limited options available for immediate intervention. Bite prevention through personal protective technologies (PPT), such as topical mosquito repellents or repellent-impregnated clothing, may help to decrease biting rates and, therefore, the risk of disease in groups most susceptible to adverse outcomes from Zika virus. However, achieving high uptake and compliance with PPT can be challenging.

Methodology/Principal findings

To gain an insight into the knowledge and concerns of pregnant women surrounding Zika and their opinions regarding PPT, particularly repellent clothing, a focus group study was carried out with pregnant women, women of reproductive age, and semi-structured interviews with their male partners in two cities in Colombia. The discussions revealed shortfalls in basic knowledge of Zika virus, with several pregnant participants reporting being unaware of the potential for Zika-related congenital malformations. Although participants generally considered Zika to be a significant personal threat, most rated it as less of a concern than dengue or diarrheal diseases. Overall, repellent clothing and other forms of PPT were viewed as effective, although some participants expressed concerns over the high costs of repellents, and safety fears of regular contact with repellent chemicals, which they perceived as potentially harmful. Plant-derived repellents were considered to be safer than synthetic chemical repellents. Discussions also highlighted that health centers were the preferred source of information on bite-reduction.

Conclusions/Significance

Achieving high uptake and compliance with PPT in populations most at risk of adverse outcomes from Zika infection requires engaging key users in open dialogue to identify and address any practical issues regarding PPT use, and concerns over safety. The findings presented here suggest that educational campaigns should strongly emphasize the risks associated with Zika during pregnancy, and discuss safety profiles of approved synthetic repellents and the availability of EPA-approved plant-based repellents. In addition, the economic and political context should be a major consideration when evaluating personal mosquito-repellent strategies.

Although mosquito personal protective technologies (PPT), such as topical DEET or permethrin impregnated clothing, show high efficacy in laboratory studies, they frequently achieve poor population uptake. This is likely due to numerous factors, including high costs, dislike of the feel or smell of the product, and safety fears over the repellent chemicals. The targeted use of PPT to those at elevated risk of severe disease, such as pregnant women in Zika endemic regions, may help mitigate adverse outcomes from Zika virus infection. To explore ways of increasing the appeal of PPT, a focus group study was performed with pregnant women and women of reproductive age in two cities in Colombia. Although almost all participants had heard of Zika, not all pregnant women were aware of the potential for Zika-related birth defects. PPT products were generally viewed as effective, although many expressed fears that repeated exposure to chemicals may affect fetal development. There was limited trust over repellent-manufacturer claims of safety, and women from low socioeconomic groups believed PPT products to be unaffordable. Participants identified health centers as trusted sources of bite-prevention education, suggesting health workers should emphasize safety and efficacy of approved repellents.

Safety of Over-the-Counter Medications in Pregnancy

Approximately 90% of pregnant women use medications while they are pregnant including both over-the-counter (OTC) and prescription medications. Some medications can pose a threat to the pregnant woman and fetus with 10% of all birth defects directly linked to medications taken during pregnancy. Many medications have documented safety for use during pregnancy, but research is limited due to ethical concerns of exposing the fetus to potential risks. Much of the information gleaned about safety in pregnancy is collected from registries, case studies and reports, animal studies, and outcomes management of pregnant women. Common OTC categories of readily accessible medications include antipyretics, analgesics, nonsteroidal anti-inflammatory drugs, nasal topicals, antihistamines, decongestants, expectorants, antacids, antidiarrheal, and topical dermatological medications. We review the safety categories for medications related to pregnancy and provide an overview of OTC medications a pregnant woman may consider for management of common conditions.

Evidence-Based Process for Prioritizing Positive Behaviors for Promotion: Zika Prevention in Latin America and the Caribbean and Applicability to Future Health Emergency Responses

To maximize the impact of Zika prevention programming efforts, a prioritization process for social and behavior change programming was developed based on a combination of research evidence and programmatic experience. Prioritized behaviors were: application of mosquito repellent, use of condoms, removing unintentional standing water, covering and scrubbing walls of water storage containers, seeking prenatal care, and seeking counseling on family planning if not planning to get pregnant.

Since the 2015 Zika outbreak in Latin America and the Caribbean, a plethora of behavior change messages have been promoted to reduce Zika transmission. One year after the United States Agency for International Development (USAID) initiated its Zika response, more than 30 variants of preventive behaviors were being promoted. This situation challenged social and behavior change (SBC) programming efforts that require a coordinated response and agreed upon set of focus behaviors to be effective. To support USAID implementing partners in harmonizing prevention efforts to reduce Zika infection, we developed an evidence-based process to identify behaviors with the highest potential to reduce Zika infection and transmission. We compiled a full list of behaviors and selected the most promising for a full evidence review. The review included systematic keyword searches on Google Scholar, extraction of all relevant published articles on Aedes-borne diseases between 2012 and 2018, review of seminal papers, and review of gray literature. We examined articles to determine each behavior's potential effectiveness in preventing Zika transmission or reducing the Aedes aegypti population. We also developed assessment criteria to delineate the ease with which the target population could adopt each behavior, including: (1) required frequency; (2) feasibility of the behavior; and (3) accessibility and cost of the necessary materials in the setting. These behaviors were refined through a consensus-building process with USAID's Zika implementing partners, considering contextual factors. The resulting 7 evidence-based preventive behaviors have high potential to strengthen SBC programming's impact in USAID's Zika response: (1) apply mosquito repellent, (2) use condoms during pregnancy, (3) remove standing water, (4) cover water storage containers, (5) clean/remove mosquito eggs from water containers, (6) seek antenatal care, and (7) seek family planning counseling. This case study documents a flexible process that can be adapted to inform the prioritization of behaviors when there is limited evidence available, as during many emergency responses.

Use of mosquito repellents to protect against Zika virus infection among pregnant women in Brazil

OBJECTIVES

To evaluate the use of repellents among pregnant women as a protective measure against infection with the Zika virus.

STUDY DESIGN

Pregnant women (n = 177) were interviewed between November 2016 and February 2017 at Basic Health Units in the city of Propriá, state of Sergipe, Brazil. Two units were located in rural areas and eight in urban regions.

METHODS

Data were analysed using descriptive statistical methods, the Chi-squared test or Fisher's exact test and odds ratios. The independent variables were grouped by analysis of the main components, and adherence to the use of the repellent was analysed by the logistic regression method.

RESULTS

A total of 100 women reported using repellents at the time of the interview (56%). The use of repellents was greater among women with higher levels of education (83%) than those with only high school (68%) or elementary school (36%) education. Women assisted by the income transfer programme (Bolsa Família) presented a 2.27 times greater chance of not using repellents compared with pregnant women who were not receiving benefits of the programme. Regarding the logistic regression model, we observed that low economic and social conditions of pregnant women, as well as their lack of advice, had a negative effect on the use of repellents.

CONCLUSIONS

Repellents were generally used as a preventive measure in pregnant women with higher levels of schooling and fewer children. The relatively high cost of repellents was the main reason for non-use.

Repellency Assessment of Nepeta cataria Essential Oils and Isolated Nepetalactones on Aedes aegypti

There is an increased need for improved and affordable insect repellents to reduce transmission of rapidly spreading diseases with high mortality rates. Natural products are often used when DEET cannot be afforded or accessed and when consumers choose not to use a synthetic repellent. The essential oils from two newly bred Nepeta cataria (catnip) plants representing two different chemotypes and their respective isolated nepetalactone isomers were evaluated as mosquito repellents against Aedes aegypti mosquitoes that transmit the Zika and Dengue virus in a one choice landing rate inhibition assay. A dose response curve was generated for each treatment and a time course analysis of repellency was performed over 24 hours with a N. cataria essential oil sample. The results indicate that all essential oil samples and their respective purified nepetalactone isomers were able to achieve greater than 95% repellency. Between two and four hours, the ability to repel more than 95% of the mosquitoes diminished. At the lowest concentrations tested, the nepetalactones and crude essential oil samples were more effective than DEET at reducing the number of mosquito landings.

Zika Virus Infection in Children

Zika virus is a mosquito-borne Flavivirus responsible for symptomatic and asymptomatic infections in humans. Zika was first identified in Africa as a cause of sporadic febrile illness. Beginning in 2015, Zika virus infection was identified in Brazil and linked with several symptomatic infections. Notably, congenital infections were observed with marked neurologic abnormalities. Diagnosis relies on detection of Zika virus by real-time polymerase chain reaction or by the presence of anti-Zika antibodies. Treatment of this viral illness remains supportive; however, proactive screening and interventions are indicated in the treatment of infants with symptomatic congenital infection.

Urinary concentrations of 3-(diethylcarbamoyl)benzoic acid (DCBA), a major metabolite of N,N-diethyl-m-toluamide (DEET) and semen parameters among men attending a fertility center

STUDY QUESTION

Are specific gravity (SG)-adjusted urinary concentrations of 3-(diethylcarbamoyl)benzoic acid (DCBA) associated with semen parameters among men attending an academic fertility center?

SUMMARY ANSWER

Our study did not demonstrate any association between SG-adjusted urinary DCBA concentrations and semen parameters among men attending an academic fertility center.

WHAT IS KNOWN ALREADY

N,N-Diethyl-m-toluamide (DEET) is the most common active ingredient in consumer insect repellents. The recent rise in public health concerns regarding mosquito-borne diseases such as Zika, have led to an increased use of DEET insect repellents, especially among couples planning pregnancy. Animal studies have observed reproductive toxicity from DEET exposure. However, the reproductive health effects of DEET and its metabolites on human reproduction are unknown.

STUDY DESIGN, SIZE, DURATION

Between 2007 and 2015, 90 men participating in a prospective cohort study at the Massachusetts General Hospital Fertility Center provided 171 urine samples and 250 semen samples for analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The urinary concentrations of DEET, N,N-diethyl-3-hydroxymethylbenzamide (DHMB) and DCBA were quantified by isotope-dilution tandem mass spectrometry and adjusted by SG. We used linear mixed models to evaluate the association between tertiles of SG-adjusted urinary DCBA concentrations and semen parameters (semen volume, sperm concentration, total sperm count, progressive motility, total progressive motility count, normal morphology and total normal morphology count), adjusting for covariates. DEET and DHMB were not considered for analysis because of the low percentage of detectable concentrations (<7%). Effect modification by BMI and smoking status was explored.

MAIN RESULTS AND THE ROLE OF CHANCE

Participants had a median age of 36 years and BMI of 27 kg/m2, and 68% had never smoked. The SG-adjusted geometric mean DCBA urinary concentration was 2.20 μg/l, with 85% detection frequency. The majority of semen parameters fell within the normal range with the exception of progressive motility, where 64% of the men had values below the WHO 2010 lower reference limits. SG-adjusted urinary DCBA concentrations were not associated with semen parameters in unadjusted or adjusted models. Men in the highest tertile of SG-adjusted urinary DCBA concentrations had comparable semen parameters to men in the lowest tertile (2.59 vs. 2.88 ml for semen volume, 47.9 vs. 45.8 million/ml for sperm concentration, 116 vs. 118 million for total sperm count, 25 vs. 24% for progressive sperm motility, and 6.1 vs. 5.8% for morphologically normal sperm). In addition, BMI and smoking status did not modify the associations.

LIMITATIONS REASONS FOR CAUTION

We had a relatively small sample size with similar socioeconomic backgrounds and with overall relatively low urinary concentrations of DEET biomarkers. However, our sample size was enough to detect moderate differences with at least 80% statistical power, between the first and third tertiles of urinary DCBA concentrations. Limitations also include possible misclassification of DCBA exposure and difficulties in extrapolating the findings to the general population.

WIDER IMPLICATIONS OF THE FINDINGS

Our study found no associations between urinary concentrations of DCBA, a major metabolite of the insect repellent DEET, and semen parameters in men presenting for infertility treatment. While these results are reassuring, further studies including larger sample sizes and higher exposures are warranted.

STUDY FUNDING/COMPETING INTEREST(S)

The project was financed by the National Institute of Health grants R01ES022955 and R01ES009718 and by grant P30ES000002 from the National Institute of Environmental Health Sciences (NIEHS). None of the authors has any conflicts of interest to declare. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

TRIAL REGISTRATION NUMBER

N/A.

Current Research on the Safety of Pyrethroids Used as Insecticides

Pyrethroids are synthetic derivatives of natural pyrethrins extracted from Chrysanthemum cinerariaefolium. They are 2250 times more toxic to insects than to vertebrates due to insects' smaller size, lower body temperature and more sensitive sodium channels. In particular, three pyrethroid compounds, namely deltamethrin, permethrin, and alpha-cypermethrin, are commonly used as insecticides and are recommended for in-home insect control because they are considered to be relatively non-toxic to humans in all stages of life. However, recent data show that they are not completely harmless to human health as they may enter the body through skin contact, by inhalation and food or water, and absorption level depending on the type of food. Permethrin seems to have an adverse effect on fertility, the immune system, cardiovascular and hepatic metabolism as well as enzymatic activity. Deltamethrin induces inflammation, nephro- and hepatotoxicity and influences the activity of antioxidant enzymes in tissues. Alpha-cypermethrin may impair immunity and act to increase glucose and lipid levels in blood. The aim of the review is to provide comprehensive information on potential hazards associated to human exposure to deltamethrin, permethrin and alpha-cypermethrin. The results of presented studies prove that the insecticides must be used with great caution.

Detection and Prevention of Perinatal Infection: Cytomegalovirus and Zika Virus

Congenital cytomegalovirus is the most common viral congenital infection, and affects up to 2% of neonates. Significant sequelae may develop after congenital cytomegalovirus, including hearing loss, cognitive defects, seizures, and death. Zika virus is an emerging virus with perinatal implications; a congenital Zika virus syndrome has been identified, and includes findings such as microcephaly, fetal nervous system abnormalities, and neurologic sequelae after birth. Screening, diagnosis, prevention, and treatment of these perinatal infections are reviewed in this article.

Trends in insect repellent formulations: A review

The use of natural and synthetic repellents, marketed in different pharmaceutical forms, is growing in the world due to the emerging vector-borne viral diseases as Dengue, Zika, Chikungunya, Yellow Fever and Malaria. The choice of the ideal formulation will depend on a series of factors to be analyzed: type of repellent active (natural or synthetic), pharmaceutical forms (spray, lotion, cream, gel), action time duration (short or long), environment of exposure and the user (adult, pregnant women, children, newborn). The most used repellents are DEET, IR3535 (Ethyl Butylacetylaminopropionate) (EB), Icaridin (Picaridin) and essential oils, each of them presenting advantages and disadvantages. DEET is the oldest and the most powerful repellent available in the market, thus being the reference standard. For this reason, there are many classic formulations available in the market containing the chemical component DEET in spray forms and lotions. However, due to its toxicity, DEET is not recommended for children up to 6 months and pregnant women. DEET has been an option along with other market-shared products as IR3535 and Icaridin (Picaridin), which present less toxicity in their composition. IR3535 is the less toxic and may be prescribed for children over 6 months of age and pregnant women so that they have been the best option because of the lower toxicity levels presented. IR3535 is the one that has the lowest toxicity level among the three options and may be prescribed for children above 6 months of age and pregnant women. Icaridin is as potent as DEET, but less toxic, and has the advantage of having the long-lasting action among the aforementioned repellents. The new formulations have been based on controlled release systems (CRS). The CRSs for repellents comprise polymer micro/nanocapsules, micro/solid lipid nanoparticles, nanoemulsions/microemulsions, liposomes/niosomes, nanostructured hydrogels and cyclodextrins. There are many formulations based on micro and nanocapsules containing DEET and essential oils to increase repellent action time duration and decrease permeation and consequently, systemic toxicity. The development of new formulations for the IR3535 and Icaridin is a research field yet to be explored. The current trend is the use of natural repellent actives such as essential oils, which present low toxicity, do not harm the environment, but present reduced repellent action time due to rapid evaporation after skin application. CRSs have been used as vehicle of natural repellents to improve long-lasting repellent action, reduce skin permeation and systemic effects.

Zika clinical updates: implications for pediatrics

PURPOSE OF REVIEW

Zika virus (ZIKV), a mosquito-borne flavivirus, has gained recognition over the past few years as an important new cause of congenital infection. As a result, it is critical that pediatricians understand its epidemiology, clinical presentation, clinical sequelae, and management.

RECENT FINDINGS

The recent ZIKV epidemiology, clinical presentation of acute infection in children and complications, perinatal infection, and congenital infection will be summarized in this ZIKV review. This will be followed by a brief summary on ZIKV diagnosis, management, treatment, and prevention.

SUMMARY

The field of clinical research in ZIKV has rapidly evolved over recent months. It is critical that pediatricians continue to stay up-to-date with the continuously evolving understanding of the clinical aspects of ZIKV to ensure optimal identification and management of affected infants and children. Given the recent changes in Centers for Disease Control and Prevention guidelines to limit screening of asymptomatic pregnant women in the United States with possible ZIKV exposure, comprehensive ZIKV clinical knowledge becomes even more crucial.

Travel-Related Infections Among Pregnant Travellers to the Tropics: An Overview

Infectious diseases acquired during travel pose a significant health risk to pregnant travellers, who are more susceptible to both acquiring certain infections and developing severe complications. A review of the literature focusing on recent evidence-based guidelines was conducted with attention to tropical infections in the pregnant patient. A summary meant to serve as a succinct reference for health care professionals caring for pregnant women is presented. Magnitude of risk, clinical features, management, and preventive strategies of major travel-acquired infections of pertinence to the pregnant traveller are summarized, including malaria, arboviral infections, foodborne infections, helminthic infections, and influenza. Tables with details on specific infections within each group and guidance for reducing travel-related health risks in the pregnant patient are presented.

Travel Characteristics and Pretravel Health Care Among Pregnant or Breastfeeding U.S. Women Preparing for International Travel

OBJECTIVE

To study characteristics and preventive interventions of adult pregnant and breastfeeding travelers seeking pretravel health care in the United States.

METHODS

This cross-sectional study analyzed data (2009-2014) of pregnant and breastfeeding travelers seen at U.S. travel clinics participating in Global TravEpiNet. Nonpregnant, nonbreastfeeding adult female travelers of childbearing age were used for comparison. We evaluated the prescription of malaria chemoprophylaxis and antibiotics for this population as well as the administration of three travel-related vaccines: hepatitis A, typhoid, and yellow fever. We also evaluated use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis and influenza vaccines, because these are widely recommended in pregnancy.

RESULTS

Of 21,138 female travelers of childbearing age in Global TravEpiNet, 170 (0.8%) were pregnant and 139 (0.7%) were breastfeeding. Many traveled to destinations endemic for mosquito-borne illnesses, including malaria (pregnant: 95%; breastfeeding: 94%), dengue (pregnant: 87%; breastfeeding: 81%), or yellow fever (pregnant: 35%; breastfeeding: 50%). Compared with nonpregnant, nonbreastfeeding adult female travelers, eligible pregnant travelers were less likely to be vaccinated against hepatitis A (28% compared with 51%, P<.001) and typhoid (35% compared with 74%, P<.001). More than 20% of eligible pregnant travelers did not receive influenza vaccination. Yellow fever vaccine was occasionally provided to pregnant and breastfeeding travelers traveling to countries entirely endemic for yellow fever (6 [20%] of 30 pregnant travelers and 18 [46%] of 39 breastfeeding travelers). Half of pregnant travelers and two thirds of breastfeeding travelers preparing to travel to malaria-holoendemic countries received a prescription for malaria prophylaxis.

CONCLUSION

Most pregnant and breastfeeding travelers seen for pretravel health consultations traveled to destinations with high risk for vector-borne or other travel-related diseases. Destination-specific preventive interventions were frequently underused.

Evolution of Knowledge, Awareness, and Practices regarding Zika Virus from 2016 to 2017

Objective

Our team created a knowledge, attitudes, and practice (KAP) survey in order to assess changes over time in healthcare provider and community member awareness of Zika virus symptoms, transmission, treatment, and current and future concerns.

Study Design

The cross-sectional survey was issued at an academic medical center in Washington, DC, and via an online link to healthcare providers and community members between June and August 2016. Survey distribution was then repeated the following year, from March to April 2017. Outcomes were compared by survey year and healthcare provider versus community member status using SAS Program Version 9.4.

Results

Significant differences in knowledge, attitudes, and practices existed between 2016 and 2017 survey time points. By 2017, more respondents had knowledge of various Zika virus infection characteristics; however healthcare provider knowledge also waned in certain areas. Attitudes towards Zika virus infection displayed an overall decreased concern by 2017. Practice trends by 2017 demonstrated fewer travel restrictions to Zika-endemic areas and increased mosquito protective measures within the US.

Conclusions

Our results provide novel insight into the transformation of knowledge, attitudes, and practice of community members and healthcare providers regarding Zika virus since its declaration as a public health emergency of international concern in 2016.

Zika Virus: a Review from the Virus Basics to Proposed Management Strategies

This review aims to summarize the body of knowledge available on Zika virus to date. A comprehensive review of the scientific literature on Zika virus was performed with the aim to stress relevant aspects for healthcare professionals in the non-endemic areas. For several years, the Zika virus infection was considered an extremely rare exotic disease with poor clinical relevance. However, Zika virus has recently gained the attention of the scientific community and public opinion since the virus spread to the Pacific islands and the South America in an unprecedented epidemic, and additionally due to the definitive evidence that the infection could be complicated by Guillain-Barré syndrome, passed through vertical transmission, and result in central nervous system abnormalities (including microcephaly) of the fetus. Studies and scientific evidence on the complications associated with Zika virus infection are growing day by day. It is advisable that the healthcare professionals working in non-endemic areas maintain full awareness on this issue in order to practice proper management of the imported cases of Zika virus infection.