The Health System in Costa Rica: Focus on the Management of Diabetes Mellitus

Costa Rica's health system was established in 1941 by the president at the time, Rafael Angel Calderon Guardia. Since then, the public health system has expanded, and a private system was also introduced. Diabetes management differs greatly between both systems, as well as the medications available. Publicly, the system faces many challenges when treating diabetes; including a limited range and selection of medications, as well as a blatant lack of support (nutritional, physical, and psychological). Privately, the costs adjacent to a diabetes diagnosis represent an unbearable burden to some patients, with medications such as a weekly dose of 1.0 mg of semaglutide representing approximately 47.5% of Costa Rica's minimum wage. Despite its flaws, both systems provide the Costa Rican population with options for treatment. The Caja Costarricense de Seguro Social covers around 90% of the population, which puts Costa Rica on par with developed countries.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Willingness to Get a COVID-19 Vaccine and Its Potential Predictors in Costa Rica: A Cross-Sectional Study

Since 2020, the COVID-19 pandemic has had a significant impact on morbidity and mortality around the world. As one of the most successful and cost-effective health interventions for preventing infectious diseases, immunization against SARS-CoV-2, is at the moment the most effective strategy for controlling the current pandemic. Despite the high vaccine acceptance rates that countries such as Costa Rica have shown in the past, the public acceptance of the COVID-19 vaccine is still uncertain. The purpose of this study was to examine adults’ willingness to get a novel COVID-19 vaccine and its potential predictors in Costa Rica. We conducted a cross-sectional study comprising a sample of 4717 adult participants living in Costa Rica who participated in a voluntary electronic survey regarding their intent to get a future COVID-19 vaccine. Results suggest that a high percentage (86.1%) of Costa Ricans aged 18 or more would be willing to be vaccinated once a safe and effective vaccine is approved and distributed in the country. Some relevant significant predictors of willingness to get a COVID-19 vaccine in Costa Rica were higher income, being male, work in the health care sector, and having a relative or a close acquaintance diagnosed with COVID-19. Our findings suggest that it is essential to concentrate efforts on the immediate development of culturally appropriate communication, dissemination, and implementation strategies to maximize immunization against SARS-CoV-2 in Costa Rica.

Impact of COVID-19 on the surgical volume of general surgery residents as main surgeons in a National Training Program in Costa Rica: A cross-sectional study

ABSTRACT

To quantify the impact of coronavirus disease 19 (COVID-19) on the surgical volume of residents' medical practice in Costa Rica's General Surgery Residency Program.The COVID-19 pandemic has caused a significant disruption in people's lives. Health systems worldwide have been forced to adapt to the new normal, which has posed a challenge for medical residency programs, especially in the surgical field.This transversal study includes the surgical records of all residents of the General Surgery program who worked as main surgeons at the Mexico Hospital of the Costa Rican Social Security between December 23, 2019, and June 25, 2020.As main surgeons, a total of 10 residents performed 291 pre-pandemic surgeries and 241 pandemic surgeries.When comparing the distribution of procedures performed by residency levels, it is observed that the postgraduate year -2 increased the number of procedures performed during the pandemic period (pre-pandemic 19% vs pandemic 27%, P = .028). There was no statistically significant difference between the pre-pandemic and pandemic periods in the remaining levels.When comparing the procedures by unit, a statistically significant decrease was observed in the Endocrine-Abdominal Wall Unit (pre-pandemic 18.3% vs pandemic 5.4%, P < .001). Conversely, a statistically significant increase was identified in Surgical Emergencies Unit procedures (40.0% vs post 51.7%, P = .007). No statistically significant differences were observed in the remaining the Units.The COVID-19 pandemic had no statistically significant effect on surgeries performed by residents of the General Surgery Residency Program as main surgeons in a national training center in Costa Rica. The Department's timely measures and pro-resident attitude were the key reasons for the above results.

The current prevalence of asthma, allergic rhinitis, and eczema related symptoms in school-aged children in Costa Rica

OBJECTIVE

Asthma prevalence in Costa Rica is among the highest worldwide. We aimed to determine the prevalence of asthma among school-age children in the Central Highland Area of Costa Rica.

METHODS

Cross-sectional study using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was performed. Parents or guardians of children aged 6-13 years completed written questionnaires.

RESULTS

Total of 2817 school-aged children returned these questionnaires (74.1% return rate). The prevalence of asthma, rhinitis, and eczema was 21.9%, 42.6%, and 19.2%, respectively. The co-existence of the 3 diseases was seen in 22.6% of children with asthma. Boys had a slightly higher prevalence of these conditions, and younger children had higher prevalence of asthma and eczema, but lower prevalence of rhinitis than older children. The use of acetaminophen and antibiotics in the first 12 months of life showed a significant association with the prevalence of asthma, rhinitis, and eczema. Wheezing with exercise, dry cough at night, and ever rhinitis was highly associated with asthma symptoms in the last 12 months. In contrast, no association was found between children exposed to smoking at home. Frequent traffic next to the house was reported more frequently by the parents of children with asthma, although no significant association was found.

CONCLUSION

The prevalence of asthma showed a significant decrease compared to previous studies. However, there was an unexpected high prevalence of rhinitis. Exposure to acetaminophen and antibiotic during the first year of life was highly associated with asthma symptoms.

Detection of Dirofilaria immitis and other arthropod-borne filarioids by an HRM real-time qPCR, blood-concentrating techniques and a serological assay in dogs from Costa Rica

BACKGROUND

Canine filarioids are important nematodes transmitted to dogs by arthropods. Diagnosis of canine filariosis is accomplished by the microscopic identification of microfilariae, serology or PCR for filarial-DNA. The aim of this study was to evaluate a molecular assay for the detection of canine filariae in dog blood, to compare its performance to other diagnostic techniques, and to determine the relationship between microfilarial concentration and infection with other vector-borne pathogens.

METHODS

Blood samples from 146 dogs from Costa Rica were subjected to the detection of canine filarioids by four different methods: the microhematocrit tube test (MCT), Knott's modified test, serology and a high resolution melt and quantitative real-time PCR (HRM-qPCR). Co-infection with other vector-borne pathogens was also evaluated.

RESULTS

Fifteen percent of the dogs were positive to Dirofilaria immitis by at least one of the methods. The HRM-qPCR produced distinctive melting plots for the different filarial worms and revealed that 11.6% of dogs were infected with Acanthocheilonema reconditum. The latter assay had a limit of detection of 2.4x10⁻⁴ mf/μl and detected infections with lower microfilarial concentrations in comparison to the microscopic techniques and the serological assay. The MCT and Knott's test only detected dogs with D. immitis microfilaremias above 0.7 mf/μl. Nevertheless, there was a strong correlation between the microfilarial concentration obtained by the Knott's modified test and the HRM-qPCR (r = 0.906, p < 0.0001). Interestingly, one dog was found infected with Cercopithifilaria bainae infection. Moreover, no association was found between microfilaremia and co-infection and there was no significant difference in microfilarial concentration between dogs infected only with D. immitis and dogs co-infected with Ehrlichia canis, Anaplasma platys or Babesia vogeli.

CONCLUSIONS

This is the first report of A. reconditum and C. bainae in Costa Rica and Central America. Among the evaluated diagnostic techniques, the HRM-qPCR showed the most sensitive and reliable performance in the detection of blood filaroids in comparison to the Knott's modified test, the MCT test and a serological assay.

Leotia cf. lubrica forms arbutoid mycorrhiza with Comarostaphylis arbutoides (Ericaceae)

Arbutoid mycorrhizal plants are commonly found as understory vegetation in forests worldwide where ectomycorrhiza-forming trees occur. Comarostaphylis arbutoides (Ericaceae) is a tropical woody plant and common in tropical Central America. This plant forms arbutoid mycorrhiza, whereas only associations with Leccinum monticola as well as Sebacina sp. are described so far. We collected arbutoid mycorrhizas of C. arbutoides from the Cerro de la Muerte (Cordillera de Talamanca), Costa Rica, where this plant species grows together with Quercus costaricensis. We provide here the first evidence of mycorrhizal status for the Ascomycete Leotia cf. lubrica (Helotiales) that was so far under discussion as saprophyte or mycorrhizal. This fungus formed arbutoid mycorrhiza with C. arbutoides. The morphotype was described morphologically and anatomically. Leotia cf. lubrica was identified using molecular methods, such as sequencing the internal-transcribed spacer (ITS) and the large subunit (LSU) ribosomal DNA regions, as well as phylogenetic analyses. Specific plant primers were used to confirm C. arbutoides as the host plant of the leotioid mycorrhiza.

Banana production systems: identification of alternative systems for more sustainable production

Large-scale, monoculture production systems dependent on synthetic fertilizers and pesticides, increase yields, but are costly and have deleterious impacts on human health and the environment. This research investigates variations in banana production practices in Costa Rica, to identify alternative systems that combine high productivity and profitability, with reduced reliance on agrochemicals. Farm workers were observed during daily production activities; 39 banana producers and 8 extension workers/researchers were interviewed; and a review of field experiments conducted by the National Banana Corporation between 1997 and 2002 was made. Correspondence analysis showed that there is no structured variation in large-scale banana producers' practices, but two other banana production systems were identified: a small-scale organic system and a small-scale conventional coffee-banana intercropped system. Field-scale research may reveal ways that these practices can be scaled up to achieve a productive and profitable system producing high-quality export bananas with fewer or no pesticides.

Epidemiology of Invasive Fungal Infections in Latin America

The pathogenic role of invasive fungal infections (IFIs) has increased during the past two decades in Latin America and worldwide, and the number of patients at risk has risen dramatically. Working habits and leisure activities have also been a focus of attention by public health officials, as endemic mycoses have provoked a number of outbreaks. An extensive search of medical literature from Latin America suggests that the incidence of IFIs from both endemic and opportunistic fungi has increased. The increase in endemic mycoses is probably related to population changes (migration, tourism, and increased population growth), whereas the increase in opportunistic mycoses may be associated with the greater number of people at risk. In both cases, the early and appropriate use of diagnostic procedures has improved diagnosis and outcome.

Tobacco industry success in Costa Rica: the importance of FCTC article 5.3

OBJECTIVE

To analyze how the tobacco industry influenced tobacco control policymaking in Costa Rica.

MATERIALS AND METHODS

Review of tobacco industry documents, tobacco control legislation, newspaper articles, and interviewing of key informants.

RESULTS

During the mid-to-late 1980s, Health Ministry issued several advanced (for their time) smoking restriction decrees causing British American Tobacco (BAT) and Philip Morris International (PMI) to strengthen their political presence there, resulting in passage of a weak 1995 law, which, as of August 2011, remained in effect. Since 1995 the industry has used Costa Rica as a pilot site for Latin American programs and has dominated policymaking by influencing the Health Ministry, including direct private negotiations with the tobacco industry which violate Article 5.3's implementing guidelines of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC).

CONCLUSIONS

The Costa Rica experience demonstrates the importance of vigorous implementation of FCTC Article 5.3 which insulates public health policymaking from industry interference.

[Prevalence of and screening for ADHD in Costa Rica]

This research project sought to estimate the prevalence of Attention-Deficit/Hyperactivity Disorder (ADHD) and to determine if the Swanson Nolan and Pelham Rating Scale IV (SNAP-IV) Spanish version is a useful screening tool in a population of Costa Rican school children. The SNAP-IV Spanish version was given to the parents and teachers of 425 children aged 5 to 13 (mean 8.8). All subjects were also assessed with the Swanson, Kotkin, Agler, M-Flynn and Pelham Scale (SKAMP), along with diagnostic confirmation by clinical interview. The sensitivity and specificity of the SNAP-IV was assessed as a predictor of DSM-IV ADHD diagnosis. The point prevalence of Attention Deficit Hyperactivity Disorder (ADHD) in this sample was 5%. The prevalence of ADHD among girls was 7%, while that among boys was 4%. The optimal screen was the teacher-rated SNAP-IV at a 20% cutoff, which had a sensitivity of 96% and specificity of 82%. Parent sensitivities were lower than teacher sensitivities. SNAP-IV teacher ratings with a cutoff isolating the top 20% of scores correctly categorized 87% of children.

Lack of association to a NRG1 missense polymorphism in schizophrenia or bipolar disorder in a Costa Rican population

A missense polymorphism in the NRG1 gene, Val>Leu in exon 11, was reported to increase the risk of schizophrenia in selected families from the Central Valley region of Costa Rica (CVCR). The present study investigated the relationship between three NRG1 genetic variants, rs6994992, rs3924999, and Val>Leu missense polymorphism in exon 11, in cases and selected controls from an isolated population from the CVCR. Isolated populations can have less genetic heterogeneity and increase power to detect risk variants in candidate genes. Subjects with bipolar disorder (BD, n=358), schizophrenia (SZ, n=273), or unrelated controls (CO, n=479) were genotyped for three NRG1 variants. The NRG1 promoter polymorphism (rs6994992) was related to altered expression of NRG1 Type IV in other studies. The expression of NRG1 type IV in the dorsolateral prefrontal cortex (DLPFC) and the effect of the rs6994992 genotype on expression were explored in a postmortem cohort of BD, SZ, major depressive disorder (MDD) cases, and controls. The missense polymorphism Val>Leu in exon 11 was not significantly associated with schizophrenia as previously reported in a family sample from this population, the minor allele frequency is 4%, thus our sample size is not large enough to detect an association. We observed however an association of rs6994992 with NRG1 type IV expression in DLPFC and a significantly decreased expression in MDD compared to controls. The present results while negative do not rule out a genetic association of these SNPs with BD and SZ in CVCR, perhaps due to small risk effects that we were unable to detect and potential intergenic epistasis. The previous genetic relationship between expression of a putative brain-specific isoform of NRG1 type IV and SNP variation was replicated in postmortem samples in our preliminary study.

Sampling scarab beetles in tropical forests: the effect of light source and night sampling periods

Light traps have been used widely to sample insect abundance and diversity, but their performance for sampling scarab beetles in tropical forests based on light source type and sampling hours throughout the night has not been evaluated. The efficiency of mercury-vapour lamps, cool white light and ultraviolet light sources in attracting Dynastinae, Melolonthinae and Rutelinae scarab beetles, and the most adequate period of the night to carry out the sampling was tested in different forest areas of Costa Rica. Our results showed that light source wavelengths and hours of sampling influenced scarab beetle catches. No significant differences were observed in trap performance between the ultraviolet light and mercury-vapour traps, whereas these two methods caught significantly more species richness and abundance than cool white light traps. Species composition also varied between methods. Large differences appear between catches in the sampling period, with the first five hours of the night being more effective than the last five hours. Because of their high efficiency and logistic advantages, we recommend ultraviolet light traps deployed during the first hours of the night as the best sampling method for biodiversity studies of those scarab beetles in tropical forests.

Do biological measures mediate the relationship between education and health: A comparative study

Despite a myriad of studies examining the relationship between socioeconomic status and health outcomes, few have assessed the extent to which biological markers of chronic disease account for social disparities in health. Studies that have examined this issue have generally been based on surveys in wealthy countries that include a small set of clinical markers of cardiovascular disease. The availability of recent data from nationally representative surveys of older adults in Costa Rica and Taiwan that collected a rich set of biomarkers comparable to those in a recent US survey permits us to explore these associations across diverse populations. Similar regression models were estimated on three data sets - the Social Environment and Biomarkers of Aging Study in Taiwan, the Costa Rican Study on Longevity and Healthy Aging, and the Health and Retirement Study in the USA - in order to assess (1) the strength of the associations between educational attainment and a broad range of biomarkers; and (2) the extent to which these biomarkers account for the relationships between education and two measures of health status (self-rated health, functional limitations) in older populations. The estimates suggest non-systematic and weak associations between education and high risk biomarker values in Taiwan and Costa Rica, in contrast to generally negative and significant associations in the US, especially among women. The results also reveal negligible or modest contributions of the biomarkers to educational disparities in the health outcomes. The findings are generally consistent with previous research suggesting stronger associations between socioeconomic status and health in wealthy countries than in middle-income countries and may reflect higher levels of social stratification in the US. With access to an increasing number of longitudinal biosocial surveys, researchers may be better able to distinguish true variations in the relationship between socioeconomic status and health across different settings from methodological differences.

Stressors over the life course and neuroendocrine system dysregulation in Costa Rica

OBJECTIVE

A key aspect of the increasingly popular allostatic load (AL) framework is that stressors experienced over the entire life course result in physiological dysregulation. Although core to AL theory, this idea has been little tested, and where it has been tested, the results have been mixed.

METHOD

The study analyzes the Costa Rican Study on Longevity and Healthy Aging (CRELES), a new, cross-sectional, and nationally representative survey of older Costa Rican men and women (aged between 60 and 109 years). The survey period is between 2004 and 2006, and the survey has a sample size of 2,827 individuals. This article focuses on the relationship between a variety of stressors experienced over the life course and cortisol, dehydroepiandrosterone sulfate (DHEAS), epinephrine, and norepinephrine analyzed separately and in an index.

RESULTS

There are some links between certain stressors and worse cortisol levels, but overall, almost all of the stressors examined are not associated with riskier neuroendocrine biomarker profiles.

DISCUSSION

More work is needed, in order to establish the connection between stressors experienced over the life course and resting levels of the neuroendocrine markers.

Embryonic inbreeding depression varies among populations and by mating system in Witheringia solanacea (Solanaceae)

PREMISE OF THE STUDY

Embryonic inbreeding depression is a key influence on mating system evolution and can be difficult to estimate in self-incompatible species. A pollen chase experiment was used to estimate the magnitude of embryonic inbreeding depression in Costa Rican Witheringia solanacea, a species polymorphic for self-incompatibility (SI). In a pollen chase experiment, bud self-pollinations are followed after anthesis by outcross pollinations, with a comparable pair of outcross pollinations used as a control. Lowered seed set for the self-precedence treatment indicates embryonic inbreeding depression. •

METHODS

Embryonic inbreeding depression was assayed for self-compatible (SC) individuals and for SI plants from two populations that differ quantitatively in the onset and enzymatic activity of their SI response. Microsatellite markers were used to assay the selfing rate of a sample of surviving progeny from the prior self-pollination treatment. •

KEY RESULTS

SC individuals showed no evidence of embryonic inbreeding depression. In SI plants, prior self-pollination reduced seed number by 28-70%, depending on population. Microsatellite genotyping revealed that embryonic inbreeding depression was even more severe than estimated by the phenotypic data: for mature fruits resulting from self-pollination precedence, the majority of the progeny were the result of outcross fertilization. •

CONCLUSIONS

Lineage-specific purging of recessive lethals has accompanied the evolution of SC in this species. SI populations show contrasting levels of embryonic inbreeding depression, with nearly complete embryonic lethality upon selfing in the Monteverde population. In the face of high embryonic inbreeding depression, an increase in selfing rate can evidently occur only under severe pollen limitation.

Morphological and Molecular Characterization of Some Peritrichs (Ciliophora: Peritrichida) from Tank Bromeliads, Including Two New Genera: Orborhabdostyla and Vorticellides

Using standard methods, we studied the morphology and 18S rDNA sequence of some peritrich ciliates from tank bromeliads of Costa Rica, Jamaica, and Ecuador. The new genus Orborhabdostyla differs from Rhabdostyla by the discoidal macronucleus. Two species from the literature and a new species from Ecuadoran tank bromeliads are combined with the new genus: O. previpes (Claparède and Lachmann, 1857) nov. comb., O. kahli (Nenninger, 1948) nov. comb., and O. bromelicola nov. spec. Orborhabdostyla bromelicola is a slender species with stalk-like narrowed posterior half and operculariid/epistylidid oral apparatus. An epistylidid relationship is also suggested by the gene sequence. Vorticella gracilis, described by Dujardin (1841) from French freshwater, belongs to the V. convallaria complex but differs by the yellowish colour and the number of silverlines. The classification as a distinct species is supported by the 18S rDNA, which differs nearly 10% from that of V. convallaria s. str. Based on the new data, especially the very stable yellowish colour, we neotypify V. gracilis with the Austrian population studied by Foissner (1979). Vorticella gracilis forms a strongly supported phyloclade together with V. campanula, V. fusca and V. convallaria, while Vorticellides astyliformis and Vorticella microstoma branch in a separate, fully-supported clade that includes Astylozoon and Opisthonecta. The new genus Vorticellides comprises five small (usually < 60 μm), barrel-shaped species with two epistomial membranes: V. aquadulcis (Stokes, 1887) nov. comb., V. astyliformis (Foissner, 1981) nov. comb., V. platysoma (Stokes, 1887) nov. comb., V. infusionum (Dujardin, 1841) nov. comb., and V. (Spinivorticellides) echini (King, 1931) nov. comb. Two of these species are redescribed in the present study: V. astyliformis and V. aquadulcis, which is neotypified with a Costa Rican population. Pseudovorticella bromelicola nov. spec. differs from the congeners by the location of the two contractile vacuoles and the number of silverlines.

Urban structure and dengue fever in Puntarenas, Costa Rica

Dengue is currently the most important arboviral disease globally and is usually associated with built environments in tropical areas. Remotely sensed information can facilitate the study of urban mosquito-borne diseases by providing multiple temporal and spatial resolutions appropriate to investigate urban structure and ecological characteristics associated with infectious disease. In this study, coarse, medium and fine resolution satellite imagery (Moderate Resolution Imaging Spectrometer, Advanced Spaceborne Thermal Emission and Reflection Radiometer and QuickBird respectively) and ground-based data were analyzed for the Greater Puntarenas area, Costa Rica for the years 2002-04. The results showed that the mean normalized difference vegetation index (NDVI) was generally higher in the localities with lower incidence of dengue fever during 2002, although the correlation was statistically significant only in the dry season (r=-0.40; p=0.03). Dengue incidence was inversely correlated to built area and directly correlated with tree cover (r=0.75, p=0.01). Overall, the significant correlations between dengue incidence and urban structural variables (tree cover and building density) suggest that properties of urban structure may be associated with dengue incidence in tropical urban settings.

El Niño Southern Oscillation and vegetation dynamics as predictors of dengue fever cases in Costa Rica

Dengue fever (DF) and dengue hemorrhagic fever (DHF) are growing health concerns throughout Latin America and the Caribbean. This study focuses on Costa Rica, which experienced over 100 000 cases of DF/DHF from 2003 to 2007. We utilized data on sea-surface temperature anomalies related to the El Niño Southern Oscillation (ENSO) and two vegetation indices derived from the Moderate Resolution Imaging Spectrometer (MODIS) from the Terra satellite to model the influence of climate and vegetation dynamics on DF/DHF cases in Costa Rica. Cross-correlations were calculated to evaluate both positive and negative lag effects on the relationships between independent variables and DF/DHF cases. The model, which utilizes a sinusoid and non-linear least squares to fit case data, was able to explain 83% of the variance in weekly DF/DHF cases when independent variables were shifted backwards in time. When the independent variables were shifted forward in time, consistently with a forecasting approach, the model explained 64% of the variance. Importantly, when five ENSO and two vegetation indices were included, the model reproduced a major DF/DHF epidemic of 2005. The unexplained variance in the model may be due to herd immunity and vector control measures, although information regarding these aspects of the disease system are generally lacking. Our analysis suggests that the model may be used to predict DF/DHF outbreaks as early as 40 weeks in advance and may also provide valuable information on the magnitude of future epidemics. In its current form it may be used to inform national vector control programs and policies regarding control measures; it is the first climate-based dengue model developed for this country and is potentially scalable to the broader region of Latin America and the Caribbean where dramatic increases in DF/DHF incidence and spread have been observed.

Initiation of absconding-swarm emigration in the social wasp Polybia occidentalis

When a colony of the swarm-founding social wasp Polybia occidentals loses its nest to severe weather or predation, the adult population evacuates and temporarily clusters on nearby foliage. Most of the adults remain inactive in the cluster, while foragers bring in nectar and scout wasps search the surrounding area for a new nesting site. After several hours, the scouts stimulate the rest of the swarm to leave the cluster and follow their pheromone trail to the chosen site. How scouts communicate to their swarm-mates that a site has been chosen and how they induce the swarm to depart are unknown. Video records of six Costa Rican swarms were used to quantitatively document changes in the frequencies of social behaviors leading to swarm departure. This was accomplished by going backward through the video record and following the behavior of individuals prior to their departure. Analysis of the behavior of scouts and inactive wasps indicated an increase in the frequency with which scouts bump into inactive wasps prior to swarm departure, as well as a shift in the behavior of inactive wasps from primarily receiving bumps to bumping others before departure. Thus, bumping is propagated by recently activated individuals before they take off. These observations suggest that not only is bumping an activation stimulus that causes swarm members to depart for the new nest site, but it is contagious, leading to its amplification throughout the swarm.

Surprising SES Gradients in mortality, health, and biomarkers in a Latin American population of adults

BACKGROUND

To determine socioeconomic status (SES) gradients in the different dimensions of health among elderly Costa Ricans.

HYPOTHESIS

SES disparities in adult health are minimal in Costa Rican society.

METHODS

Data from the Costa Rican Study on Longevity and Healthy Aging study: 8,000 elderly Costa Ricans to determine mortality in the period 2000-2007 and a subsample of 3,000 to determine prevalence of several health conditions and biomarkers from anthropometry and blood and urine specimens.

RESULTS

The ultimate health indicator, mortality, as well as the metabolic syndrome, reveals that better educated and wealthier individuals are worse off. In contrast, quality of life-related measures such as functional and cognitive disabilities, physical frailty, and depression all clearly worsen with lower SES. Overall self-reported health (SRH) also shows a strong positive SES gradient. Traditional cardiovascular risk factors such as diabetes and cholesterol are not significantly related to SES, but hypertension and obesity are worse among high-SES individuals. Reflecting mixed SES gradients in behaviors, smoking and lack of exercise are more common among low SES, but high calorie diets are more common among high SES.

CONCLUSIONS

Negative modern behaviors among high-SES groups may be reversing cardiovascular risks across SES groups, hence reversing mortality risks. But negative SES gradients in healthy years of life persist.

Geographic variation in host-specificity and parasitoid pressure of an herbivore (geometridae) associated with the tropical genus piper (piperaceae)

The extraordinary diversity of tropical herbivores may be linked to hostplant specialization driven in part by variation in pressure from natural enemies. We quantified levels of host-specificity and parasitoid attack for the specialist herbivore, Eois (Geometridae). The goals of this research were to examine: 1) whether Eois are specialized on the genus Piper (Piperaceae) and if hostplant specialization varies geographically; 2) whether Eois are equally vulnerable to parasitoid attack across different geographic regions and by the same parasitoid families; and 3) whether parasitism levels vary with precipitation and elevation. Based on over 15,000 rearings, we found Eois caterpillars feeding exclusively on Piper. However, we did not detect geographic differences in host-specificity; each Eois species fed on an average of two Piper species. Parasitism levels of Eois varied significantly with climate and topography; Eois were most vulnerable to parasitoid attack in moist versus dry and wet forests and at low versus high elevations. The diversity of parasitoid families reared from Eois was greater in Ecuador and Costa Rica than in Panama, where parasitoids were primarily in the family Braconidae. The quantitative evidence for host-specificity provides support for the hypothesis that Eois are specialized on Piper. Our results also reveal that Eois are exposed to a mosaic of potential selective pressures due to variation in parasitoid attack over a large spatial scale.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in wet and dry habitat; significantly more colonies were found in dry habitat. Seventeen of 19 nests built on slopes of > 5 degrees inclination were positioned on the downward side of the tree, possibly using the trunk as a shield against runoff during rain showers. Moisture and pH inside nests were significantly different from adjacent soil. These results suggest that water influences the ground nesting habits of P. clavata, thus ecological differences between comparatively wet and dry portions of tropical forests may arise from the relative abundance of this ant species.

Wedding biodiversity inventory of a large and complex Lepidoptera fauna with DNA barcoding

By facilitating bioliteracy, DNA barcoding has the potential to improve the way the world relates to wild biodiversity. Here we describe the early stages of the use of cox1 barcoding to supplement and strengthen the taxonomic platform underpinning the inventory of thousands of sympatric species of caterpillars in tropical dry forest, cloud forest and rain forest in northwestern Costa Rica. The results show that barcoding a biologically complex biota unambiguously distinguishes among 97% of more than 1000 species of reared Lepidoptera. Those few species whose barcodes overlap are closely related and not confused with other species. Barcoding also has revealed a substantial number of cryptic species among morphologically defined species, associated sexes, and reinforced identification of species that are difficult to distinguish morphologically. For barcoding to achieve its full potential, (i) ability to rapidly and cheaply barcode older museum specimens is urgent, (ii) museums need to address the opportunity and responsibility for housing large numbers of barcode voucher specimens, (iii) substantial resources need be mustered to support the taxonomic side of the partnership with barcoding, and (iv) hand-held field-friendly barcorder must emerge as a mutualism with the taxasphere and the barcoding initiative, in a manner such that its use generates a resource base for the taxonomic process as well as a tool for the user.

Human rabies: a reemerging disease in Costa Rica?

Two human rabies cases caused by a bat-associated virus variant were identified in September 2001 in Costa Rica, after a 31-year absence of the disease in humans. Both patients lived in a rural area where cattle had a high risk for bat bites, but neither person had a definitive history of being bitten by a rabid animal. Characterization of the rabies viruses from the patients showed that the reservoir was the hematophagous Vampire Bat, Desmodus rotundus, and that a sick cat was the vector.