Factors associated with hand hygiene adherence among healthcare workers in Guatemala during the COVID-19 pandemic.

BACKGROUND: Healthcare-associated infections are prevalent in low- and middle-income countries and may be reduced through proper hand hygiene (HH) adherence during patient care. AIM: We produced and distributed alcohol-based hand rub (ABHR) to 19 public primary- and secondary-level healthcare facilities in Quetzaltenango, Guatemala, and carried out HH observations to assess healthcare workers' (HCWs) HH adherence, and to identify factors associated with this practice. HH adherence was defined as washing hands with soap and water or using ABHR. METHODS: Observations were conducted before (2021, baseline) and after (2022, follow-up) ABHR distribution to evaluate the evolution of HH practices over time. Bivariate comparisons and mixed-effects logistic regression models were used to explore associations between HH adherence and the following independent variables: healthcare facility level, type of contact performed, timing of HH performance, occupational category of HCW and materials present (e.g., water, soap, ABHR). FINDINGS: We observed 243 and 300 patient interactions among 67 and 82 HCWs at each time point, respectively. HH adherence was low for both observation periods (40% at baseline and 35% at follow-up). HCWs were more likely to adhere to HH during invasive contacts, after patient contact, and if the HCW was a physician. CONCLUSION: HH adherence varied by scenario, which underscores the importance of addressing multiple determinants of behaviour change to improve adherence. This requires interventions implemented with a multi-modal approach that includes both increasing access to HH materials and infrastructure, as well as HH education and training, monitoring and feedback, reminders, and promoting a HH safety culture.

Informal sale of antibiotics in Guatemalan convenience stores before and after implementation of federal antibiotic dispensing legislation.

BACKGROUND: Convenience stores in Guatemala provide essential consumer goods in communities, but many dispense antibiotics illegally. Federal legislation, passed in August of 2019, requires prescriptions for antibiotic purchase at pharmacies but it is unclear if this legislation is enforced or if it has any impact on unlawful sales of antibiotics. METHODS: To determine if antibiotic availability changed in convenience stores, we carried out a repeated measures study collecting antibiotic availability data before and after implementation of the dispensing regulation. RESULTS: There was no statistical difference in the proportion of convenience stores that sold antibiotics before and after antibiotic regulations [66.6% (295/443) and 66.7% (323/484), respectively, P>0.96], nor in the number of stores selling amoxicillin [55.5% (246/443) and 52.3% (253/484), respectively, P>0.96], but fewer stores (20%) sold tetracycline capsules after regulation was passed (P<0.05). For stores visited both before and after passage of legislation (n=157), 15% stopped selling antibiotics while 25% started selling antibiotics. Antibiotics from convenience stores were reportedly sold for use in people and animals. CONCLUSIONS: Antibiotics remain widely available in convenience stores consistent with no significant change in the informal sector after implementation of prescription requirements for pharmacies. Importantly, effects from regulatory change could have been masked by potential changes in antibiotic use during the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic.

Risk factors for domestic infestation by the Chagas disease vector, Triatoma dimidiata in Chiquimula, Guatemala.

In Guatemala prior to control initiatives, the main vectors of Trypanosoma cruzi, the causative agent of Chagas disease, were Rhodnius prolixus and Triatoma dimidiata. This study conducted in 2006 in the department of Chiquimula recorded a high level of T. dimidiata infestation and an absence of R. prolixus in all surveyed communities. In Guatemala, the presence of T. dimidiata as domestic, peridomestic and sylvatic populations results in control difficulties as houses are re-infested from the surrounding environment. Entomological surveys, the current method used to select houses in need of control efforts, are labour intensive and time consuming. A time- and cost-effective way to prioritize houses for evaluation and subsequent treatment is the stratification of houses based on the risk of triatomine infestation. In the present study, 17 anthropogenic risk factors were evaluated for associations with house infestation of T. dimidiata including: wall, floor and roof type. There was an increased likelihood of domestic infestation with T. dimidiata associated with the presence of dirt floors (18/29; OR 8.075, 95% CI 2.13-30.6), uncoated bajareque walls (12/17; OR 4.80, 95% CI 1.35-17.1) and triatomine-like faeces on walls (16/26; OR 3.89, 95% CI 1.19-12.7). These factors could be used to target control of T. dimidiata to communities with an increased risk of being infested.

Culex flavivirus isolates from mosquitoes in Guatemala.

A new strain of Culex flavivirus (family Flaviviridae, genus Flavivirus, CxFV), an insect virus first described in Japan, was isolated from adult Culex quinquefasciatus Say (Diptera: Culicidae) collected in 2006 from Izabal Department on the Caribbean coast of Guatemala. Mosquito pools were assayed for flavivirus RNA by using flavivirus group-specific primers that amplified a 720-bp region of the nonstructural (NS) 5 gene by standard reverse transcriptase-polymerase chain reaction. From 210 pools (1,699 mosquitoes), eight tested positive, and six of these mosquito pools produced virus isolates in Aedes albopictus Skuse C6/36 cells. Nucleotide sequence comparison of the eight flavivirus RNA-positive pools showed that there was 100% identity among them, and phylogenetic analysis of the NS5 and envelope gene regions indicated that they represent a strain of the recently described CxFV from Japan. This is the first report of an insect flavivirus from Central America.

Chromosomal variation and genome size support existence of cryptic species of Triatoma dimidiata with different epidemiological importance as Chagas disease vectors.

The wide geographical distribution of Triatoma dimidiata, one of the three major vectors of Chagas disease, ranges from Mexico to northern Peru. Since this species occupies a great diversity of artificial and natural ecotopes, its eradication is extremely difficult. In order to assist control efforts, we used chromosome analyses and DNA amount as taxonomic markers to study genetic variability in populations of T. dimidiata from Mexico, Guatemala, El Salvador and Colombia. We differentiated three groups or cytotypes defined by characteristic chromosome C-banding patterns and genome size measured by flow cytometry. The three cytotypes are restricted to different geographic locations. Cytotype 1 occurs in Mexico (excluding Yucatán), Guatemala (excluding Petén), El Salvador and Colombia. Cytotype 2 occurs in Yucatán and cytotype 3 occurs in Petén. Cytotype 1, commonly associated with domestic and peridomestic environments but also inhabiting sylvatic ecotopes, is the most widespread and with major epidemiological significance. In contrast, the Yucatán cytotype inhabits wild ecotopes but increasingly enters houses, while the Petén cytotype appears exclusively sylvatic. We suggest that these cytotypes represent cryptic species of T. dimidiata with different epidemiological relevance as Chagas disease vectors. Poor ability to colonize human dwellings, together with their restricted geographic distribution, indicate that the Yucatán and Petén putative species probably have much less epidemiological significance than cytotype 1. Thus, the genetic markers we describe are powerful tools to differentiate cryptic species in T. dimidiata with different epidemiological significance, contributing to planning the most effective control measures.

The impact of vector control on Triatoma dimidiata in the Guatemalan department of Jutiapa.

In 2000, a national control operation against the triatomine vectors of Trypanosoma cruzi, based on house spraying with residual pyrethroid insecticides, was initiated in Guatemala. The impact of the operation against Triatoma dimidiata in the most heavily infested department, Jutiapa, was evaluated by pre- and post-spraying surveys of the vector populations. Of the houses checked for Tri. dimidiata in the baseline surveys, 18.3% were found to be infested with the bug, and in 12.1% of the villages investigated more than half of the houses were found to be infested. The later survey was conducted after 24,250 houses and their associated peridomestic structures (in the 336 villages in which >5% of the houses had been found infested in the pre-spraying survey) had been sprayed. As a result of just this one round of spraying, the mean percentage of houses found infested in each of the villages surveyed twice fell from 36.0% to 8.9%. After the spraying, the percentage of houses infested in each sprayed village was never >50%, and the houses in 35.2% of the sprayed villages that were re-surveyed appeared to have been completely cleared of triatomine bugs. Re-infestation and colonization were mainly observed inside the houses, probably indicating that some indoor bugs survived the spraying round. If the department of Jutiapa is to be freed and kept free from domestic infestation, the efficacy of the insecticide spraying needs to be improved, spraying techniques need to be reviewed, and insecticides need to be re-applied at regular intervals. An effective vector-surveillance system (preferably one in which community participation is encouraged) is also essential.

Impact of residual spraying on Rhodnius prolixus and Triatoma dimidiata in the department of Zacapa in Guatemala.

As a vector control program to control Chagas disease in Guatemala, residual spraying of Rhodnius prolixus and Triatoma dimidiata was performed, and its impact was measured in the department of Zacapa. In order to identify infested villages and determine the degree of infestation, a baseline entomological survey to identify municipalities infested with vectors followed by an additional vector survey in areas known to be infested was conducted. Residual spraying using pyrethroid insecticides was performed at all the villages identified as being infested with the vectors. The residual spraying was shown to be highly effective against both vectors by the decrease in infestation indices after spraying. Analysis of the cost-effectiveness of the spraying showed that the average cost of insecticides per house is high when compared with that in Southern Cone countries.

Impact of residual spraying on Rhodnius prolixus and Triatoma dimidiata in the department of Zacapa in Guatemala

As a vector control program to control Chagas disease in Guatemala, residual spraying of Rhodnius prolixus and Triatoma dimidiata was performed, and its impact was measured in the department of Zacapa. In order to identify infested villages and determine the degree of infestation, a baseline entomological survey to identify municipalities infested with vectors followed by an additional vector survey in areas known to be infested was conducted. Residual spraying using pyrethroid insecticides was performed at all the villages identified as being infested with the vectors. The residual spraying was shown to be highly effective against both vectors by the decrease in infestation indices after spraying. Analysis of the cost-effectiveness of the spraying showed that the average cost of insecticides per house is high when compared with that in Southern Cone countries

Bacterial symbiosis and paratransgenic control of vector-borne Chagas disease.

The triatomine vectors of Chagas disease are obligate haematophagous insects, feeding on vertebrate blood throughout their entire developmental cycle. As a result of obtaining their nutrition from a single food source, their diet is devoid of certain vitamins and nutrients. Consequently, these insects harbour populations of bacterial symbionts within their intestinal tract, which provide the required nutrients that are lacking from their diet. We have isolated and characterised symbiont cultures from various triatomine species and developed a method for genetically transforming them. We can then reintroduce them into their original host species, thereby producing stable paratransgenic insects in which we are able to express heterologous gene products. Using this methodology, we have generated paratransgenic Rhodnius prolixus that are refractory for infection with Trypanosoma cruzi. Two examples of potentially refractory genes are currently being expressed in paratransgenic insects. These include the insect immune peptide cecropin A and active single chain antibody fragments. We have also developed an approach that would allow introduction of genetically modified bacterial symbionts into natural populations of Chagas disease vectors. This approach utilises the coprophagic behaviour of these insects, which is the way in which the symbionts are transmitted among bug populations in nature. The production and ultimate release of transgenic or paratransgenic insects for public health applications is potentially very promising but also worthy of much careful consideration with respect to environmental, political, and human safety concerns.

Seroprevalence of Trypanosoma cruzi infection in three rural communities in Guatemala.

A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0% to 20.8% for the three communities, with a mean of 15.1%. Log-linear models showed that seroprevalence was significantly related to age (P < 0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P = 0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P = 0.01).

Expression of a functional antibody fragment in the gut of Rhodnius prolixus via transgenic bacterial symbiont Rhodococcus rhodnii.

Expression within insects of foreign antiparasitic gene products via microbial symbionts could be used to prevent transmission of vector-borne pathogens to vertebrate hosts. Genetically transformed symbiotic bacteria Rhodococcus rhodnii expressed functional antibody fragments (rDB3 encoding murine V(H)/K which binds progesterone) that were exported into the gut lumen of the triatomine bug Rhodnius prolixus (Hemiptera: Reduviidae), a vector of Chagas disease. Transgenic symbionts were maintained in successive nymphal instars and adults of Rhodnius prolixus despite competition with native untransformed Rhodococcus rhodnii. This is the first description of a functional mammalian antibody fragment expressed in an insect. Our system is a model for constructing paratransgenic insects (insects carrying transformed symbionts) with compromised ability to transmit pathogens.

Mitochondrial DNA sequence variation among triatomine vectors of Chagas' disease.

Kissing bugs or triatomines (Reduviidae: Triatominae) are vectors of the Chagas' disease agent Trypanosoma cruzi. There is a current need for more sensitive tools for use in discrimination of different bug populations and species, thus allowing a better understanding of these insects as it relates to disease transmission and control. In a preliminary analysis of the mitochondrial large subunit ribosomal RNA (mtlsurRNA) and cytochrome B (mtCytB) genes, we used DNA sequencing to study species identification and phylogeny. In both examined gene regions, about 46% of nucleotide positions exhibited polymorphism. The examined region of mtCytB appears to have evolved more rapidly than the examined region of mtlsurRNA. Phylogenetic analysis of both gene fragments in the examined species produced similar results that were generally consistent with the accepted taxonomy of the subfamily. The two major tribes, Rhodniini and Triatomini, were supported, along with additional clades that corresponded to accepted species complexes within the Rhodnius and Triatoma genera. The one chief exception was that Psammolestes coreodes sorted into the Rhodnius prolixus-robustus-neglectus clade, with bootsrap values of 99% and 81%, respectively, for the mtlsurRNA and mtCytB fragments. All of the individual species examined could be distinguished at both genetic loci.

Independent selection of multiple mechanisms for pyrethroid resistance in Guatemalan Anopheles albimanus (Diptera: Culicidae).

Isofemale lines were established containing either, both, or neither of the elevated esterase and oxidase resistance mechanisms conferring pyrethroid resistance in a Guatemalan strain of Anopheles albimanus (Wiedemann). Plots of esterase and oxidase levels for individual mosquitoes from these single families correlated with data obtained using oxidase and esterase synergists in bioassays run in the bottle format. Mixed populations of pyrethroid-resistant A. albimanus adult females were selected using DDT, permethrin, or malathion; and the esterase and oxidase levels of the individual progeny were plotted. These data showed that the 3 classes of insecticide selected the 2 mechanisms differently. These results are discussed in terms of the problem of multiresistance surveillance in the field, especially concerning pyrethroid insecticides and the interaction of agricultural and public health insecticide application.

Failure to detect a Plasmodium vivax-like malaria parasite in globally collected blood samples.

Two variants of the circumsporozoite (CS) protein of Plasmodium vivax (VK210 and VK247) have been identified. Recently, a putative third CS variant of P. vivax, referred to as causing P. vivax-like malaria, has been reported from Papua New Guinea. The objective of this study was to confirm and extend findings on the global distribution of the P. vivax-like parasite. Blood samples were obtained from 126 untreated patients with P. vivax infection acquired in Central America, South America, Africa, Southeast Asia, and the Indian subcontinent. The P. vivax CS gene was amplified by polymerase chain reaction and hybridized with probes specific for the VK210, VK247, and P. vivax-like CS variants. All samples were positive for VK210, VK247, or both. No sample was positive for P. vivax-like DNA. Therefore, the existence of a third variant of P. vivax cannot be confirmed in the geographic areas studied.

Effects of permethrin-impregnated bed nets on malaria vectors of northern Guatemala.

The authors evaluated the effects on malaria vectors of bed nets impregnated with permethrin over the course of a 16-month controlled study in four communities of Northern Guatemala. Anopheles albimanus and An. vestitipennis were the known malaria vectors in the area. Households were allocated to one of three experimental groups: those receiving bed nets impregnated with 500 mg/m2 of permethrin, those receiving untreated bed nets, and those where no intervention measures were taken. The impact of the treated and untreated bed nets on mosquito abundance, behavior, and mortality was determined by indoor/outdoor night-bite mosquito collections, morning pyrethrum spray collections, inspection of bed net surfaces for dead mosquitoes, and capture-release-recapture studies. The duration of the treated nets' residual insecticide effect was assessed by modified WHO cone field bioassays, and their pyrethrin content was estimated by gas-liquid chromatography analysis. The most important observation was that fewer mosquitoes were found to be resting in the households with treated bed nets. The treated nets probably functioned by both repelling and killing vector mosquitoes. Capture-release-recapture studies showed exit rates from houses with treated nets were higher (94%) than those from control houses (72%), a finding that suggests repellency. However, no significant differences were noted between the indoor night-bite mosquito collections at houses with and without treated nets. The horizontal surfaces of treated bed nets were nearly 20 times more likely to contain dead anopheline mosquitoes than were the comparable surfaces of untreated nets. the bioassays indicated that unwashed permethrin-impregnated bed nets retained their insecticidal activity for 6 months after treatment.

Field evaluation of an enzyme-linked immunosorbent assay for estimating the sporozoite rate in Anopheles albimanus.

We have verified for specimens of Anopheles albimanus that an enzyme-linked immunosorbent assay (ELISA) used to assess Plasmodium vivax and P. falciparum sporozoite antigen rates gives results comparable to the salivary gland dissection method for estimating sporozoite rates. For 14,150 adults of An. albimanus, captured at five locations in Guatemala, we report sporozoite antigen rates of 0.03-0.57%, which correlate with the malaria prevalences at the study sites. We also present data that suggest that specimens of An. albimanus for the ELISA can be obtained more efficiently by cattle corral collections than by the human bait capture method.

A generalized approach to detection of organophosphate resistance in mosquitoes.

Insecticide bioassays and biochemical microtitre assays were compared for detection of resistance to the organophosphate insecticides malathion and fenitrothion, using inbred laboratory strains of malaria vectors Anopheles albimanus Wiedemann, An.arabiensis Patton and An.stephensi Liston. With susceptible mosquitoes, the LT100 values determined from bioassays corresponded closely with times taken to abolish the activity of acetylcholinesterase activity in biochemical assays: approximately 2 h for malathion and 3 h for fenitrothion. Resistant strains of all three anophelines showed longer survival correlated with prolonged acetylcholinesterase activity. An.albimanus strains with insensitive acetylcholinesterase survived bioassays with discriminating doses of 1 h exposure to 5% malathion or 1% fenitrothion and were judged as resistant. It is concluded that enzyme-specific microassays provide a reliable means of detecting resistant individuals, with practical advantages over bioassays which do not reveal the resistance mechanism and require large numbers of healthy mosquitoes.

Field evaluation of methods for estimating carbamate resistance in Anopheles albimanus mosquitos from a microplate assay for insensitive acetylcholinesterase.

The reliability of a published method to predict survivorship in the WHO propoxur-resistance bioassay (WHO test) from the results of a biochemical assay for detecting the insensitivity of acetylcholinesterase (AChE) is described. For biochemical assay data from three field populations of Anopheles albimanus mosquitos, the results obtained using the method did not correlate consistently with the findings of the WHO test. A modified method is then described that eliminates the effect on the assay of factors unrelated to pesticide resistance, and it is shown that this modification can be used to predict survivorship in the WHO test for mosquitos from three study sites in Guatemala. The results show that when scored visually, the insensitive AChE microplate assay is an accurate method of estimating survival in the WHO test, regardless of whether the mosquitos tested are blood-fed or not. Recommendations are given for the application and analysis of data from the insensitive AChE microplate assay for detecting and monitoring resistance to carbamate insecticides.

Effect of temperature on an enzyme assay to detect fenitrothion resistance in Anopheles albimanus mosquitos.

A laboratory strain of Anopheles albimanus Wiedemann of known fenitrothion resistance was used in the field to compare the results of the WHO test for determining fenitrothion resistance in mosquitos with those of an enzyme microplate assay. The level of resistance obtained with the enzyme assay increased with the ambient temperature, and in order to compensate for this temperature effect, the incubation time was reduced. With the adjusted incubation times, the results for the microassay from 23 degrees C to 32 degrees C were the same as those found with the WHO test. The fenitrothion resistance of a field population of A. albimanus mosquitos determined between 27 degrees C and 31 degrees C using the adjusted enzyme microassay or the WHO test did not differ in a statistically significant way.