Physiologic oxygen responses to smoking opioids: an observational study using continuous pulse oximetry at overdose prevention services in British Columbia, Canada.

BACKGROUND: In British Columbia, Canada, smoking is the most common modality of drug use among people who die of opioid toxicity. We aimed to assess oxygen saturation (SpO2) while people smoked opioids during a pilot study that introduced continuous pulse oximetry at overdose prevention services (OPS) sites. METHODS: This was an observational cohort study, using a participatory design. We implemented our monitoring protocol from March to August 2021 at four OPS. We included adults (≥ 18 years) presenting to smoke opioids. A sensor taped to participants' fingers transmitted real-time SpO2 readings to a remote monitor viewed by OPS staff. Peer researchers collected baseline data and observed the timing of participants' inhalations. We analyzed SpO2 on a per-event basis. In mixed-effects logistic regression models, drop in minimum SpO2 ≤ 90% in the current minute was our main outcome variable. Inhalation in that same minute was our main predictor. We also examined inhalation in the previous minute, cumulative inhalations, inhalation rate, demographics, co-morbidities, and substance use variables. RESULTS: We recorded 599 smoking events; 72.8% (436/599) had analyzable SpO2 data. Participants' mean age was 38.6 years (SD 11.3 years) and 73.1% were male. SpO2 was highly variable within and between individuals. Drop in SpO2 ≤ 90% was not significantly associated with inhalation in that same minute (OR: 1.2 [0.8-1.78], p = 0.261) or inhalation rate (OR 0.47 [0.20-1.10], p = 0.082). There was an association of SpO2 drop with six cumulative inhalations (OR 3.38 [1.04-11.03], p = 0.043); this was not maintained ≥ 7 inhalations. Demographics, co-morbidities, and drug use variables were non-contributory. CONCLUSIONS: Continuous pulse oximetry SpO2 monitoring is a safe adjunct to monitoring people who smoke opioids at OPS. Our data reflect challenges of real-world monitoring, indicating that greater supports are needed for frontline responders at OPS. Inconsistent association between inhalations and SpO2 suggests that complex factors (e.g., inhalation depth/duration, opioid tolerance, drug use setting) contribute to hypoxemia and overdose risk while people smoke opioids.

Feeling safer: effectiveness, feasibility, and acceptability of continuous pulse oximetry for people who smoke opioids at overdose prevention services in British Columbia, Canada.

BACKGROUND: Smoking is the most common mode of unregulated opioid consumption overall and implicated in fatal overdoses in British Columbia (BC). In part, perception of decreased risk (e.g., fewer who smoke carry naloxone kits) and limited smoking-specific harm reduction services contribute to overdose deaths. Overdose prevention services (OPS) offer supervised settings for drug use. Continuous pulse oximetry, common in acute care, allows real-time, remote oxygen monitoring. We evaluated the effectiveness of a novel continuous pulse oximetry protocol aimed at allowing physical distancing (as required by COVID-19, secluded spaces, and to avoid staff exposure to vaporized opioids), its feasibility, and acceptability at OPS for people who smoke opioids. METHODS: This was a mixed methods survey study. We developed a continuous pulse oximetry protocol in collaboration with clinical experts and people with lived/living experience of substance use. We implemented our protocol from March to August 2021 at four OPS in BC permitting smoking. We included adults (≥ 18 years) presenting to OPS to smoke opioids. Peer researchers collected demographic, health, and substance use information, and conducted structured observations. OPS clients participating in our study, OPS staff, and peer researchers completed post-monitoring surveys. We analyzed responses using a thematic inductive approach and validated themes with peer researchers. RESULTS: We included 599 smoking events. OPS clients participating in our study had a mean age of 38.5 years; 73% were male. Most (98%) reported using "down", heroin, or fentanyl; 48% concurrently used other substances (32% of whom reported stimulants); 76% reported smoking alone in the last 3 days; and 36% reported an overdose while smoking. Respondents reported that the protocol facilitated physical distancing, was easy to use, high satisfaction, improved confidence, improved sense of safety, and that they would use it again. CONCLUSIONS: Continuous pulse oximetry allowed safe physical distancing, was feasible, and acceptable in monitoring people who smoke opioids at OPS.

Multidisciplinary approach detects speciation within the kissing bug Panstrongylus rufotuberculatus populations (Hemiptera, Heteroptera, Reduviidae).

BACKGROUND: Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries, this species is found infesting and colonising domiciliary ecotopes representing an epidemiological risk factor as a vector of Trypanosoma cruzi, etiological agent of Chagas disease. In spite of this, little is known about P. rufotuberculatus genetic diversity. METHODS: Cytogenetic studies and DNA sequence analyses of one nuclear (ITS-2) and two mitochondrial DNA sequences (cyt b and coI) were carried out in P. rufotuberculatus individuals collected in Bolivia, Colombia, Ecuador and Mexico. Moreover, a geometric morphometrics study was applied to Bolivian, Colombian, Ecuadorian and French Guiana samples. OBJECTIVES: To explore the genetic and phenetic diversity of P. rufotuberculatus from different countries, combining chromosomal studies, DNA sequence analyses and geometric morphometric comparisons. FINDINGS: We found two chromosomal groups differentiated by the number of X chromosomes and the chromosomal position of the ribosomal DNA clusters. In concordance, two main morphometric profiles were detected, clearly separating the Bolivian sample from the other ones. Phylogenetic DNA analyses showed that both chromosomal groups were closely related to each other and clearly separated from the remaining Panstrongylus species. High nucleotide divergence of cyt b and coI fragments were observed among P. rufotuberculatus samples from Bolivia, Colombia, Ecuador and Mexico (Kimura 2-parameter distances higher than 9%). MAIN CONCLUSIONS: Chromosomal and molecular analyses supported that the two chromosomal groups could represent different closely related species. We propose that Bolivian individuals constitute a new Panstrongylus species, being necessary a detailed morphological study for its formal description. The clear morphometric discrimination based on the wing venation pattern suggests such morphological description might be conclusive.

Panstrongylusnoireaui, a remarkable new species of Triatominae (Hemiptera, Reduviidae) from Bolivia.

Panstrongylusnoireaui sp. nov. from Bolivia is described based on male and female specimens. Although morphologically almost indistinguishable from Panstrongylusrufotuberculatus (Champion, 1899), the new species shows remarkable chromosome and molecular features, which are very distinctive among all others Panstrongylus species. The new species is also separated by some characteristics of the processes of the endosoma of the male genitalia. An updated key for species of Panstrongylus is provided.

Revista Cubana de Informática Médica. Índice referativo 2019-2021 / Cuban Journal of Medical Informatics. Referative index 2019-2021

Se presenta el índice referativo de la Revista Cubana de Informática Médica correspondiente a los años 2019-2021. Se incluyen índices auxiliares de autor, instituciones, materias y direcciones electrónicas para facilitar el contacto con los autores y la consulta de la producción científica publicada por la revista. Se utilizó CDS/ISIS para Windows (versión 1.5.3) de la UNESCO, a partir de la cual se generaron los índices auxiliares de autor, instituciones y materias. Con ello se pretende que los profesionales, técnicos, directivos y estudiantes vinculados a esta importante disciplina en el país y el mundo, dispongan de una fuente de información para realizar investigaciones bibliográficas en este campo tan importante para la salud pública cubana(AU)

The reference index of the Cuban Journal of Medical Informatics corresponding to the years 2019-2021 is presented. Auxiliary indexes of authors, institutions, subjects and electronic addresses are included to facilitate contact with the authors and the consultation of the scientific production published by the journal. UNESCO's CDS/ISIS for Windows (version 1.5.3) was used, from which auxiliary author, institution and subject indexes were generated. With this, it is intended that professionals, technicians, managers and students linked to this important discipline in the country and the world, have a source of information to carry out bibliographic research in this field so important for Cuban public health(AU)

Multidisciplinary approach detects speciation within the kissing bug Panstrongylus rufotuberculatus populations (Hemiptera, Heteroptera, Reduviidae)

BACKGROUND Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries, this species is found infesting and colonising domiciliary ecotopes representing an epidemiological risk factor as a vector of Trypanosoma cruzi, etiological agent of Chagas disease. In spite of this, little is known about P. rufotuberculatus genetic diversity. METHODS Cytogenetic studies and DNA sequence analyses of one nuclear (ITS-2) and two mitochondrial DNA sequences (cyt b and coI) were carried out in P. rufotuberculatus individuals collected in Bolivia, Colombia, Ecuador and Mexico. Moreover, a geometric morphometrics study was applied to Bolivian, Colombian, Ecuadorian and French Guiana samples. OBJECTIVES To explore the genetic and phenetic diversity of P. rufotuberculatus from different countries, combining chromosomal studies, DNA sequence analyses and geometric morphometric comparisons. FINDINGS We found two chromosomal groups differentiated by the number of X chromosomes and the chromosomal position of the ribosomal DNA clusters. In concordance, two main morphometric profiles were detected, clearly separating the Bolivian sample from the other ones. Phylogenetic DNA analyses showed that both chromosomal groups were closely related to each other and clearly separated from the remaining Panstrongylus species. High nucleotide divergence of cyt b and coI fragments were observed among P. rufotuberculatus samples from Bolivia, Colombia, Ecuador and Mexico (Kimura 2-parameter distances higher than 9%). MAIN CONCLUSIONS Chromosomal and molecular analyses supported that the two chromosomal groups could represent different closely related species. We propose that Bolivian individuals constitute a new Panstrongylus species, being necessary a detailed morphological study for its formal description. The clear morphometric discrimination based on the wing venation pattern suggests such morphological description might be conclusive.

Cryptic speciation in the Triatoma sordida subcomplex (Hemiptera, Reduviidae) revealed by chromosomal markers.

BACKGROUND: Chagas disease vectors (Hemiptera-Reduviidae) comprise more than 140 blood-sucking insect species of the Triatominae subfamily. The largest genus is Triatoma, subdivided in several complexes and subcomplexes according to morphology, ecology and genetic features. One of them is the sordida subcomplex, involving four species: Triatoma sordida, T. guasayana, T. garciabesi and T. patagonica. Given the great morphological similarity of these species, their taxonomic identification, evolutionary relationships and population differentiation have been controversial for many years and even today remain under discussion. METHODS: We simultaneously analyzed two chromosomal markers, C-heterochromatin distribution and 45S ribosomal genes chromosomal position, of 139 specimens from several sordida subcomplex populations from Argentina, Bolivia, Brazil and Paraguay, collected both in nature and from several established insectaries. Our results were compared with COI sequences deposited in GenBank. RESULTS: We recognized five chromosomal taxa with putative hybrids, which each differ in at least one chromosome marker. Most of them present significant differences in their mtDNA sequences. CONCLUSION: The chromosomal taxa here show a significant chromosome differentiation involving changes in the C-heterochromatin content and in the ribosomal clusters position. This paper identifies several erroneously classified populations by morphological methods, delimits the geographical distribution of each taxon and proposes the existence of a new cryptic species, widely distributed in Argentina. We also suggest that sordida sibling species involve closely related as well as evolutionary distant species. Taxonomic status of each chromosomal taxon is discussed considering phenotypic and genetic results previously published.

Experimental control of Triatoma infestans in poor rural villages of Bolivia through community participation.

BACKGROUND: Triatoma infestans is the main vector of Chagas disease in the southern cone countries. Present control strategies based on indoor and outdoor residual insecticide spraying are not sufficient to control disease transmission, particularly in Bolivia. Techniques based on the management of the human environment may be good alternatives or supplements. METHODS: Social and entomological surveys were carried out in four villages of Bolivia situated in the dry inter-Andean Valleys and the Chaco region. Risk factors for house infestation by T. infestans were identified, and an eco-health intervention based on education and community participation was carried out to reduce the risks of house infestation. It consisted of implementing simple and low cost vector control techniques such as coating of mud walls, cleaning activities and removal of poultry that enter rooms to lay eggs. RESULTS: The eco-health intervention significantly reduced the number of infested bedrooms, the mean abundance of T. infestans in bedrooms and beds, especially in the Chaco region. Mud wall coating was well accepted and could be proposed as a supplementary tool to the National Program of Chagas Disease Control to enhance the effects of insecticide sprayings. CONCLUSIONS: Even if cleaning activities were still neglected, community participation proved to be effective in reducing house infestation.

Susceptibility and resistance to deltamethrin of wild and domestic populations of Triatoma infestans (Reduviidae: Triatominae) in Bolivia: new discoveries

Bolivia is a high-endemic country for Chagas disease, for which the principal vector is Triatoma infestans (Triatominae). This is a mainly domestic species that is also found in the wild environment. Recently, an increasing number of studies have shown the importance of Triatominae resistance to insecticides, especially in Bolivia. Data regarding the susceptibility/resistance of wild and domestic populations of T. infestans to deltamethrin are presented. For the first time, domestic populations of the department of Santa Cruz were tested, showing low resistance. Although most of the wild populations were found to be susceptible to deltamethrin, three populations from three departments showed a mortality rate of less than 100%. This result is emphasised here.

Biotin determination in food supplements by an electrochemical magneto biosensor.

An electrochemical magneto biosensor for the rapid determination of biotin in food samples is reported. The affinity reaction was performed on streptavidin-modified magnetic microbeads as a solid support in a direct competitive format. The biotinylated horseradish peroxidase enzyme (biotin-HRP) competes with free biotin in the sample for the binding sites of streptavidin on the magnetic microbeads. The modified magnetic beads were then easily captured by a magneto graphite-epoxy composite electrode and the electrochemical signal was based on the enzymatic activity of the HRP enzyme under the addition of H(2)O(2) as the substrate and o-phenilendiamine as cosubstrate. The response was electrochemically detected by square wave voltammetry. The limit of detection was 8.4×10(-8) mol L(--1) of biotin (20 µg L(--1)) with a dynamic range from 0.94 to 2.4×10(-7) mol L(--1). Biotin-fortified commercial dietary supplement and infant formula samples were evaluated obtaining good performances in the results. Total time of analysis was 40 min per 20 assays.

After five years of chemical control: colonies of the triatomine Eratyrus mucronatus are still present in Bolivia.

Chagas disease, which is caused by the parasite Trypanosoma cruzi, is transmitted to humans by blood-sucking bugs (Triatominae). Eratyrus mucronatus is a well-dispersed triatomine species, found sometimes in dwellings. In the Apolo region of Bolivia, people continue to complain of bites by this bug despite five years of chemical control. For the first time, the domiciliation process of E. mucronatus was evaluated in a zone treated by insecticide, and it was compared with a previous situation 14 years ago. Both an entomological and a serological study were carried out: 152 dwellings were visited and 491 blood samples were analyzed with Stat-Pack and ELISA tests. In 34 dwellings (23% of the total visited dwellings), 160 triatomines of all stages were collected belonging to two species, E. mucronatus (98% of the capture) and Panstrongylus geniculatus. A domiciliation of E. mucronatus is demonstrated, particularly in the peridomicile. Bugs were captured more frequently in bedrooms in the intradomicile, and in curahuas (boundary walls in rammed mud) in the peridomicile. A P. geniculatus adult was found infected with T. cruzi. No evidence of a local vectorial transmission was found. In particular, the limited effect of the insecticide on the presence of E. mucronatus and the role of the curahuas as a source of intrusion/domiciliation process are discussed.

Susceptibility and resistance to deltamethrin of wild and domestic populations of Triatoma infestans (Reduviidae: Triatominae) in Bolivia: new discoveries.

Bolivia is a high-endemic country for Chagas disease, for which the principal vector is Triatoma infestans (Triatominae). This is a mainly domestic species that is also found in the wild environment. Recently, an increasing number of studies have shown the importance of Triatominae resistance to insecticides, especially in Bolivia. Data regarding the susceptibility/resistance of wild and domestic populations of T. infestans to deltamethrin are presented. For the first time, domestic populations of the department of Santa Cruz were tested, showing low resistance. Although most of the wild populations were found to be susceptible to deltamethrin, three populations from three departments showed a mortality rate of less than 100%. This result is emphasised here.

Presence of intradomicile colonies of the triatomine bug Panstrongylus rufotuberculatus in Muñecas, La Paz, Bolivia.

Chagas disease is a tropical parasitic disease endemic to Latin America which affects more than 10 million people, and kills more than 15,000 people each year. This condition, caused by the protozoan parasite Trypanosoma cruzi, is principally transmitted by kissing bugs (Triatominae). In Bolivia, recent reports by the Departmental Health Service showed the presence of Panstrongylus rufotuberculatus in dwellings located in the Charazani Valley (La Paz). A study was then carried out in the area to evaluate the degree of domiciliation of this species, and its possible role in the transmission of Chagas disease. In seven communities, 108 dwellings were visited to actively search for the bugs and 217 people participated in a serological study to determine the prevalence of Chagas disease in the population. Nymphs and adults belonging to two species: Panstrongylus geniculatus (5 insects, 1.5%) and P. rufotuberculatus (344 insects, 98.5%) were collected. One P. rufotuberculatus was captured in a bed, while all the other specimens of this species were found in kitchens in which guinea pigs were being reared. A large bug colony has been encountered in a kitchen environment, with more than 300 specimens of all stages. None of the 201 analyzed bugs was positive for T. cruzi. The seroprevalence of Chagas disease in the human population was low (1.3%); no evidence of a local vectorial transmission was found. In conclusion, for the time being there is no evidence of vectorial transmission of Chagas disease in the region. The possible association between reared guinea pigs and the bugs is discussed. The presence of infected people, the migratory movement of the human population and the relatively high colonization process demonstrate that the region needs to be regularly controlled to prevent the area from becoming a local source of Chagas transmission.

Insecticide resistance of Triatoma infestans (Hemiptera, Reduviidae) vector of Chagas disease in Bolivia.

OBJECTIVE: To define the insecticide resistance status of Triatoma infestans to deltamethrin (pyrethroid), malathion (organophosphate) and bendiocarb (carbamate) in Bolivia. METHODS: Fifty populations of T. infestans were sampled in Bolivian human dwellings. Quantal response data were obtained by topical applications of 0.2 µl of insecticide-acetone solutions on nymphs N1 of the F1 generations. For most populations, dose-mortality relationships and resistance ratios (RR) were analysed. Discriminating concentrations were established for each insecticide with a susceptible reference strain and used on the other field populations. A tarsal-contact diagnostic test using insecticide impregnated papers was designed to rapidly identify deltamethrin-resistant populations in the field. RESULTS: Discriminating concentrations for topical applications were 5, 70 and 120 ng active ingredient per insect for deltamethrin, bendiocarb and malathion, respectively. The diagnostic concentration for deltamethrin was 0.30% for the 1-h exposure by tarsal contact. All populations sampled in human dwellings exhibited significant levels of resistance to deltamethrin, from 6 to 491 and varied among regions. Resistant populations did not recover complete susceptibility to deltamethrin when the synergist piperonyl butoxide (PBO) was used. None of the sampled populations exhibited significant resistance to bendiocarb (all RR(50) < 1.8) or malathion (all RR(50) < 2.2). CONCLUSION: In Bolivia, most 'domestic' T. infestans populations are resistant to deltamethrin. Because insecticide vector control is the only selection pressure, resistance likely originates from it. Switching from pyrethroids to organophosphates or carbamates could be a short-term solution to control this vector, but other alternative integrated control strategies should also be considered in the long term.

Anopheles of Bolivia: new records with an updated and annotated checklist.

Anopheles squamifemur has been identified from CDC light trap collections carried out at Arca de Israel, a small community located in the extreme north-east of Bolivia (Pando Department) on the banks of the river Madera, on the border with Brazil. Anopheles costai and An. forattinii have been identified in place of An. mediopunctatus which has been removed from the Bolivian list of Anopheles species. The first identification of An. trinkae in Bolivia by Dr. J.C. Lien in 1984 is cleared. The presence of An. deaneorum in Bolivia has been confirmed by our mosquito captures carried out in Guayaramerín (Pando Department, north-east of Bolivia), a border city separated from the type locality of An. deaneorum, the Brasilian city of Guajara-Mirin, by the large Mamoré River. These new findings increase to 43 the total number of known Anopheles species for Bolivia for which an updated and partially annotated checklist is given.

A physiological time analysis of the duration of the gonotrophic cycle of Anopheles pseudopunctipennis and its implications for malaria transmission in Bolivia.

BACKGROUND: The length of the gonotrophic cycle varies the vectorial capacity of a mosquito vector and therefore its exact estimation is important in epidemiological modelling. Because the gonotrophic cycle length depends on temperature, its estimation can be satisfactorily computed by means of physiological time analysis. METHODS: A model of physiological time was developed and calibrated for Anopheles pseudopunctipennis, one of the main malaria vectors in South America, using data from laboratory temperature controlled experiments. The model was validated under varying temperatures and could predict the time elapsed from blood engorgement to oviposition according to the temperature. RESULTS: In laboratory experiments, a batch of An. pseudopunctipennis fed at the same time may lay eggs during several consecutive nights (2-3 at high temperature and > 10 at low temperature). The model took into account such pattern and was used to predict the range of the gonotrophic cycle duration of An. pseudopunctipennis in four characteristic sites of Bolivia. It showed that the predicted cycle duration for An. pseudopunctipennis exhibited a seasonal pattern, with higher variances where climatic conditions were less stable. Predicted mean values of the (minimum) duration ranged from 3.3 days up to > 10 days, depending on the season and the geographical location. The analysis of ovaries development stages of field collected biting mosquitoes indicated that the phase 1 of Beklemishev might be of significant duration for An. pseudopunctipennis. The gonotrophic cycle length of An. pseudopunctipennis correlates with malaria transmission patterns observed in Bolivia which depend on locations and seasons. CONCLUSION: A new presentation of cycle length results taking into account the number of ovipositing nights and the proportion of mosquitoes laying eggs is suggested. The present approach using physiological time analysis might serve as an outline to other similar studies and allows the inclusion of temperature effects on the gonotrophic cycle in transmission models. However, to better explore the effects of temperature on malaria transmission, the others parameters of the vectorial capacity should be included in the analysis and modelled accordingly.

Optimization of a semi-nested multiplex PCR to identify Plasmodium parasites in wild-caught Anopheles in Bolivia, and its application to field epidemiological studies.

Without an adequate DNA extraction protocol, the identification of Plasmodium species in whole mosquitoes by PCR is difficult because of the presence of reaction inhibitors from the insects. In this study, eight DNA extraction protocols were tested, from which a chelex-based protocol was selected. Then a semi-nested multiplex PCR technique that detects and distinguishes among the four human Plasmodium species in single mosquitoes and in pools of up to 100 mosquitoes was optimized. The technique was used to detect P. vivax in wild-caught Anopheles pseudopunctipennis from a village in the Andean valleys of Bolivia in May 2003. The prevalence of infection was 0.9%. This is the first direct evidence of P. vivax transmission by this vector in this country. The extraction and PCR technique presented here can be useful to: (1) estimate Plasmodium prevalence in Anopheles populations in low prevalence areas where large numbers of individual mosquitoes would need to be processed to obtain a reliable estimate; (2) incriminate Anopheles species as malaria vectors; (3) identify all the circulating Plasmodium species in vectors from an area; (4) detect mixed infections in mosquitoes; and (5) detect mosquitoes with low-level parasite infections.

Laboratory colonization of Anopheles pseudopunctipennis (Diptera: Culicidae) without forced mating.

Anopheles pseudopunctipennis is one of the main malaria vectors in the Andean regions of South America. Few experimental data exist on this species because it is not very available in laboratories due to its eurygamic status that makes colony maintenance difficult. Indeed, individuals do not mate in the confined space of insectary cages. To avoid this problem, forced artificial mating can be used. However, this technique is time consuming, requires a well-trained technician, and is inadequate for easy mass production, which is sometimes necessary for certain experimental works. This study presents a technique based on exposure of adult mosquitoes to a blue stroboscopic light for 20 min during several nights, which encourages them to copulate naturally under laboratory conditions. After some generations, a self-free-mating strain was obtained. The technique is simple, inexpensive and is probably effective whatever the An. pseudopunctipennis strain considered.

Host choice and human blood index of Anopheles pseudopunctipennis in a village of the Andean valleys of Bolivia.

BACKGROUND: The Human Blood Index (HBI, proportion of bloodmeals of a mosquito population obtained from man) is relevant to epidemiological assessment and to the modification of measures to interrupt malaria transmission since the vectorial capacity of the vector varies as the square of the HBI. Anopheles pseudopunctipennis is a main malaria vector in South America. Unfortunately, few data exist concerning HBI values in its range of distribution and none from Bolivia where this species is considered as an important malaria vector in the central Andes. METHODS: The host choice of An. pseudopunctipennis has been studied in Mataral, a characteristic village of the central Andes of Bolivia. Mosquito host feeding preference experiments (equal accessibility to host in homogenous environment) were monitored using baited mosquito nets in latin square designs. Host feeding selection experiments (natural feeding pattern in heterogeneous environment) was measured by bloodmeal analysis, using ELISA to determine the origin of blood. Mosquito bloodmeals were collected on various occasions, using various techniques in a variety of sampling sites. A survey of the possible blood sources has also been carried out in the village. Data were analysed with the forage ratio method. RESULTS: An. pseudopunctipennis chooses amongst hosts. Sheep, goats, donkeys and humans are the preferred hosts, while dogs, pigs and chicken are rarely bitten. An. pseudopunctipennis has an opportunistic behaviour, in particular within the preferred hosts. The HBI in Mataral is approximately 40% and in the central Andes, may range from 30-50%, in accordance to other findings. A high proportion of mixed meals were encountered (8%), and cryptic meals are likely more numerous. There was no difference amongst the HBI from parous and nulliparous mosquitoes. CONCLUSION: Forage ratio analysis is a powerful tool to interpret mosquito host choices. However, refinements in sampling strategies are still needed to derive accurate and precise HBIs that could be computed to compare or follow epidemiological situations. The low antropophily of An. pseudopunctipennis, associated with changing environmental conditions, leads to unstable malaria (Plasmodium vivax) transmission in the central Andes. The opportunistic behaviour of this vector may be used to attract mosquitoes to insecticide. Zooprophylaxis is a promising alternative control strategy.