Delirium de emergencia en anestesia pediátrica / Emergency delirium in pediatric anesthesia

Emergency delirium (ED) is characterized by inattention, irritability, disorientation, and hyperactivity that occurs in the period of early anesthetic awakening. It resolves spontaneously and apparently without sequelae, but it is a cause of anxiety for parents who see their children not responding in the way they normally would. The incidence reported in the literature is variable and depends on the definition used, but it is described between 10%-80%. It is associated with the use of powerful halogenated gases, such as sevoflurane and desflurane. Some risk factors for its appearance are age, type of surgery, duration of the intervention and preoperative anxiety. Its diagnosis is clinical and other causes of agitation must be ruled out prior to its diagnosis. There are various pharmacological and non-pharmacological strategies that have been tried to prevent its appearance. The treatment is pharmacological using drugs that produce transient sedation, such as propofol, opioids or dexmedetomidine.

El delirium de emergencia (DE) es un cuadro de inatención, irritabilidad, desorientación e hiperactividad que se produce en el período del despertar anestésico precoz. Se resuelve espontáneamente y aparentemente sin secuelas, pero es una causa de ansiedad en padres que ven a sus hijos que no responden de la forma que normalmente lo harían. La incidencia reportada en la literatura es variable y depende de la definición utilizada, pero se describe entre 10% ­ 80%. Se asocia al uso de gases halogenados potentes, como son el sevoflurano y desflurano. Algunos factores de riesgo para su aparición son la edad, tipo de cirugía, duración de la intervención y ansiedad preoperatoria. Su diagnóstico es clínico y debe descartarse otras causas de agitación previo a su diagnóstico. Existen diversas estrategias farmacológicas y no farmacológicas que se han intentado para prevenir su aparición. El tratamiento es farmacológico utilizando fármacos que produzcan sedación transitoria, como son el propofol, opioides o midazolam.

Ética de la Salud Pública: propuesta sobre los principios fundamentales que guían las responsabilidades éticas del estado en el contexto pandemia COVID-19 / Proposal on the principles that should guide the ethical responsibilities of the state during the COVID-19 pandemic

On March 11, 2020, the World Health Organization (WHO) stated that the number of cases of COVID-19 multiplied by 13 outside China, with a threefold increase in the number of affected countries. The WHO expressed its concern about the alarming levels of spread and severity of the outbreak, declaring the pandemic. This pandemic context is generating a social pact that seeks to ensure collective protection over individual freedoms. To meet the challenge, Governments must make decisions based on the principles that govern the State- These should consider the differences and particularities of those affected, without diverting attention from collective social protection. The following is a proposal on the ethical principles that should guide a State that makes decisions in public health emergencies.

[Proposal on the principles that should guide the ethical responsibilities of the state during the COVID-19 pandemic]. / Ética de la Salud Pública: propuesta sobre los principios fundamentales que guían las responsabilidades éticas del estado en el contexto pandemia COVID-19.

On March 11, 2020, the World Health Organization (WHO) stated that the number of cases of COVID-19 multiplied by 13 outside China, with a threefold increase in the number of affected countries. The WHO expressed its concern about the alarming levels of spread and severity of the outbreak, declaring the pandemic. This pandemic context is generating a social pact that seeks to ensure collective protection over individual freedoms. To meet the challenge, Governments must make decisions based on the principles that govern the State- These should consider the differences and particularities of those affected, without diverting attention from collective social protection. The following is a proposal on the ethical principles that should guide a State that makes decisions in public health emergencies.

[Temporal variation in the place of death in Chile from 1997 to 2014]. / Tendencia de las defunciones ocurridas en mayores de 1 año según lugar de ocurrencia y su relación con características sociodemográficas, Chile 1997-2014.

BACKGROUND: The place of death is a fundamental indicator for the debate on equity and access to health care. AIM: To describe the place of death of the deceased population over 1 year of age in Chile between the years 1997 and 2014. To analyze tendencies in this variable and its association with socio-demographic characteristics. MATERIAL AND METHODS: Time series study covering deaths occurred between 1997 and 2014 in Chile. National death records were used, provided by the Department of Health Statistics and Information (DEIS) of the Chilean Ministry of Health. The following variables were chosen: place of death (home, hospital, other), sex, marital status, age, level of education, activity and area of residence. Temporal trends were evaluated using Prais Winsten regressions. Logistic regression was used to assess the association of the place of death with socio-demographic characteristics. RESULTS: Between 1997 and 2014 there were 1,576,392 deaths, at a mean age of 69 years (p25-p75:60-83 years). No temporal variations in the place of death were observed with the Prais Winsten regression, hospital (P-W coefficient (coef) = 0.06 (confidence intervals (CI): -0.30; 0.19), p = 0.64), home (P-W coef = -0.03 (CI: -0.15; 0.09), p = 0.57), and other places (P-W coef = 0.07; (CI: -0.08 - 0.22), p = 0.32). The multivariate analysis showed that being women under 70 years of age, being married or widowed, having a higher educational level, being inactive and living in a rural area were factors associated with a greater chance of dying at home. CONCLUSIONS: No significant temporal variation in the place of death was observed.

Tendencia de las defunciones ocurridas en mayores de 1 año según lugar de ocurrencia y su relación con características sociodemográficas, Chile 1997-2014 / Temporal variation in the place of death in Chile from 1997 to 2014

Background: The place of death is a fundamental indicator for the debate on equity and access to health care. Aim: To describe the place of death of the deceased population over 1 year of age in Chile between the years 1997 and 2014. To analyze tendencies in this variable and its association with socio-demographic characteristics. Material and Methods: Time series study covering deaths occurred between 1997 and 2014 in Chile. National death records were used, provided by the Department of Health Statistics and Information (DEIS) of the Chilean Ministry of Health. The following variables were chosen: place of death (home, hospital, other), sex, marital status, age, level of education, activity and area of residence. Temporal trends were evaluated using Prais Winsten regressions. Logistic regression was used to assess the association of the place of death with socio-demographic characteristics. Results: Between 1997 and 2014 there were 1,576,392 deaths, at a mean age of 69 years (p25-p75:60-83 years). No temporal variations in the place of death were observed with the Prais Winsten regression, hospital (P-W coefficient (coef) = 0.06 (confidence intervals (CI): −0.30; 0.19), p = 0.64), home (P-W coef = −0.03 (CI: −0.15; 0.09), p = 0.57), and other places (P-W coef = 0.07; (CI: −0.08 - 0.22), p = 0.32). The multivariate analysis showed that being women under 70 years of age, being married or widowed, having a higher educational level, being inactive and living in a rural area were factors associated with a greater chance of dying at home. Conclusions: No significant temporal variation in the place of death was observed.

Pathological Findings in Wild Rats (Rattus rattus) Captured at Guafo Island, Northern Chilean Patagonia.

The black rat (Rattus rattus) is an invasive species and potential reservoir of significant pathogens of man, domestic animals and wildlife. During the 2012-2014 austral summers, 201 black rats were captured and examined on the uninhabited Guafo Island, in Northern Chilean Patagonia (43.593029°S, 74.713481°W). The mite Ornithonyssus bacoti caused lymphoplasmacytic and eosinophilic dermatitis in all infected rats (105/210, 52%), but no skin lesions were observed in rats infected with Nosopsyllus spp. and Plocopsylla spp. fleas. Eighty-eight rats (44%) had mild lymphoplasmacytic and eosinophilic enterocolitis and 61 of these rats were infected with the nematode Heterakis spumosa. In the liver, 63 animals (31%) had areas of necrosis with histiocytic and eosinophilic inflammation associated with multiple Calodium hepaticum eggs, and in 15 cases there was co-infection with several Taenia taeniaeformis strobilocerci. Mild interstitial lymphoplasmacytic sialadenitis with intranuclear inclusion bodies, suggesting cytomegalovirus infection, was observed in 28 rats (15%). In the lung, alveolar histiocytosis (69 rats, 34%) and perivascular lymphocytic infiltrates (46 rats, 23%) were the most common findings. There was mild to moderate lymphoplasmacytic interstitial nephritis in 52 rats (26%) and in 15% of these cases Leptospira spp. antigen was detected in the distal renal tubules. Some of the diseases of black rats on Guafo Island are likely to play a role in rat population dynamics. The endemic Guafo Island long-clawed mole mouse (Geoxus lafkenche), sea lions and fur seals may be at risk for infection by some of these rat pathogens.

Association of Metastasis with Clinicopathological Data in Mexican Patients with Osteosarcoma, Giant Cell Tumor of Bone and Chondrosarcoma.

BACKGROUND: Bone tumors are neoplasias with a high overall mortality; one of the main factors that reduce survival is their high capacity to develop metastases. It has been reported that finding lung metastases at diagnosis of osteosarcoma (OS), chondrosarcoma (CS) and giant cell tumor of bone (GCTb) is quite common. In this study, we inquire the relationship of metastases caused by these tumors with different clinical and pathological aspects, in order to guide medical personnel in the diagnosis and opportune treatment of metastases or micro metastases. MATERIALS AND METHODS: We collected data of 384 patients with clinical, radiological and histopathological diagnosis of OS, GCTb and CS that attended the National Rehabilitation Institute (INR) during 2006 to 2014. Chi-square and Fisher's exact tests were performed for data analysis. RESULTS: In the three tumor types, the presence of metastases at diagnosis was variable (p=0.0001). Frequency of metastases was 36.7%, 31.7% and 13.2% for OS, CS and GCTb respectively. The average age had no significant difference (p>0.05) in relation to metastases, even so, patients with OS and GCTb and metastases, were older while patients with CS and metastases were younger, in comparison to patients without metastases. Males had a higher frequency of metastases (68.2%, p = 0.09) in contrast to CS and GCTb, in which the metastases was more frequent in women with 51.9% (p = 0.44) and 57.9% (p = 0.56) respectively. Broadly, metastasis was associated with primary tumors located in the femur (44.4%), followed by the tibia (15.6%); metastases was more frequent when primary tumor of GCTb and OS were in the same bones, but were located in the hip (26.3%) for CS. CONCLUSIONS: The frequency of metastases in OS, GCTb and CS is high in our population and is determined by different clinicopathological variables related to the kind of tumor. Further studies are needed in order to evaluate metastases subsequent to diagnosis and associations with survival and clinicopathological factors , as well as to determine the sensitivity and specificity of current methods of detection.

Consideraciones del adulto mayor en UTI / Considerations of the major adult in ICU

En nuestro país, el grupo de pacientes Adultos Mayores (sobre 65 años) ha tenido un crecimiento explosivo en los últimos años, reflejo de la expectativa de vida que ha aumentado casi 10 años desde 1981 a la fecha. Con mayor frecuencia, el grupo etario en cuestión requiere ingreso a Unidades más complejas. Estudios internacionales estiman que los adultos mayores ocupan en promedio más de la mitad de los días cama de las Unidades de Tratamiento Intensivo (UTI) a nivel mundial y están cobrando relevancia en la Medicina Intensiva dada particularidades específicas que presentan para su manejo en estas unidades. En Chile, existen escasos datos acerca de ingresos y mortalidad en este grupo de pacientes en las UTI. El objetivo de esta revisión es mostrar datos epidemiológicos de la realidad local en relación a pacientes admitidos en la UTI del Centro de Pacientes Críticos (CPC) de Clínica Las Condes (CLC).

In our country the group of patients older than 65 years had a significant and explosive increment in the last years, reflecting the increased life expectancy which grew almost 10 years since 1981 until to date. With increasing frequency this older group required admission to critical care units. International studies estimate that this older group of patient occupies as an average more than half of the ICU days worldwide, therefore they are having great relevance because of the special needs for their care. In Chile, there are only scarce data about admission and outcome of these group of patients in the ICU's. The aim of this review is to describe some epidemiological data about the local reality of this group of patients admited in to the ICU of our Center for Critically Ill Patients at Clínica Las Condes.

Tumor cervical por Salmonella Typhimurium como forma de presentación clínica de SIDA en un paciente con infección por VIH / Cervical mass caused by Salmonella Typhimurium as a clinical presentation of AIDS in a HIV-positive patient

Infections due to non-typhi salmonellae (NTS) generally cause a mild and self-limited gastrointestinal disease. However, there have been reports of atypical and severe presentations in immunocompromised patients. We report the case of a male patient who consulted with a cervical mass. He was found to be HIV-positive and Salmonella Typhimurium was isolated in one blood culture and cervical mass tissue culture. We discuss the relevance of infections by NTS in immunodeficient patients because they present with more severe illness than normal population. We emphasize the importance of NTS bacteremia as a marker of underlying immunodeficiency. We present some localized infection sites reported in the literature and their relation with particular diseases. We discuss the future relevance that an early start of antiretroviral therapy (ART) may have in HIV patients with NTS acute bacteremia or focal infections. Because infections by NTS can be severe and highly lethal they must be considered in the differential diagnosis of causative organisms of localized infections and bacteremia in HIV patients.

Las infecciones por Salmonella no-Typhi (SNT) en general se tratan de cuadros gastrointestinales benignos y autolimitados en pacientes sin patología de base. Sin embargo, se han descrito presentaciones atípicas y más graves en pacientes con algún grado de compromiso inmunológico. Presentamos el caso de un paciente de sexo masculino el cual consultó por un tumor cervical de gran tamaño. Se diagnosticó infección por VIH y se aisló Salmonella Typhimurium en un hemocultivo y en un cultivo de tejido de masa cervical. Discutimos la importancia de las infecciones por Salmonella no Typhi en el grupo de pacientes con inmunosupresión debido a que presentan cuadros más graves que la población normal. Destacamos la importancia de la bacteriemia por Salmonella no Typhi como marcadoras de inmunosupresión subyacente. Presentamos algunos sitios de infección focal reportados en la literatura médica y su relación con algunas enfermedades particulares. Nos referimos a la importancia que podría tener en el futuro el inicio precoz de terapia anti-retroviral en pacientes con infección por VIH cursando bacteriemias o infecciones focales por Salmonella no Typhi. Debido a la gravedad y alta mortalidad que pueden presentar las infecciones por Salmonella no Typhi deben considerarse dentro del diagnóstico diferencial de microorganismos causantes de lesiones focales y bacteriemia en pacientes con infección por VIH.

Pathological findings in South American fur seal pups (Arctocephalus australis gracilis) found dead at Guafo Island, Chile.

During four breeding seasons (2004-2008), 78 necropsy examinations were performed on South American fur seal pups (Arctocephalus australis gracilis) found dead on Guafo Island, southern Chile (43°36'S, 74°43'W). Tissue samples from 65 pups were examined microscopically. The primary causes of death were enteritis with microscopical lesions of bacteraemia (28.2%), starvation (23.1%), drowning (21.8%), trauma (19.2%) and stillbirth (2.6%). Those pups with enteritis and microscopical lesions of bacteraemia had haemorrhagic enteritis (100%), interstitial pneumonia (86%), periportal hepatitis (73%) and vasculitis (18%). The pups that died from starvation had atrophy of hepatocytes (61%) and cholestasis (61%). The pups that drowned had bronchoalveolar oedema (65%) and foreign bodies in the airways (65%). In animals that died from trauma, the main lesions were skull fractures (67%). This range of pathological findings is within what would be expected in a healthy otariid breeding colony.

Factores pronósticos, evolución y mortalidad en el adulto inmunocompetente hospitalizado por neumonía neumocócica adquirida en la comunidad / Prognostic factors and mortality in immunocompetent adult patients hospitalized with community-acquired pneumococcal pneumonia

Background: Streptococcus pneumoniae is the main cause of community-acquired pneumonia in adults. Aim: To describe baseline characteristics, risk factors and clinical outcomes of adult patients hospitalized with pneumococcal pneumonia. Material and methods: Prospective study of adult patients admitted for a community acquired pneumonia in a clinical hospital. Immune deficient patients and those with a history of a recent hospitalization were excluded. Results: One hundred fifty one immuno-competent patients, aged 16 to 92 years, 58 percent males, were studied. Seventy-five percent had other diseases, 26 percent were admitted to the intensive care unit and 9 percent needed mechanical ventilation. There were no differences in clinical features, ICU admission or hospital length of stay among bacteremic and non-bacteremic patients. Thirty days lethality for bacteremic and non-bacteremic patients was 10.9 percent and 11.5 percent, respectively. The predictive values for lethality of Fine pneumonia severity index and CURB-65 (Confusion, Urea nitrogen, Respiratory rate, Blood pressure, 65 years of age and older) had an area under the ROC curve of 0.8 and 0.69, respectively. Multivariate analysis disclosed blood urea nitrogen over 30 mg/ dL (odds ratio (OR), 6.8), need for mechanical ventilation (OR, 7.4) and diastolic blood pressure below 50 mmHg (OR, 3.9), as significant independent predictors of death. Conclusions: Pneumococcal pneumonia was associated with a substantial rate of complications and mortality. Clinical presentation and outcome did not differ significantly among patients with and without bacteremia.

[Prognostic factors and mortality in immunocompetent adult patients hospitalized with community-acquired pneumococcal pneumonia]. / Factores pronósticos, evolución y mortalidad en el adulto inmunocompetente hospitalizado por neumonía neumocócica adquirida en la comunidad.

BACKGROUND: Streptococcus pneumoniae is the main cause of community-acquired pneumonia in adults. AIM: To describe baseline characteristics, risk factors and clinical outcomes of adult patients hospitalized with pneumococcal pneumonia. MATERIAL AND METHODS: Prospective study of adult patients admitted for a community acquired pneumonia in a clinical hospital. Immune deficient patients and those with a history of a recent hospitalization were excluded. RESULTS: One hundred fifty one immuno-competent patients, aged 16 to 92 years, 58% males, were studied. Seventy-five percent had other diseases, 26% were admitted to the intensive care unit and 9% needed mechanical ventilation. There were no differences in clinical features, ICU admission or hospital length of stay among bacteremic and non-bacteremic patients. Thirty days lethality for bacteremic and non-bacteremic patients was 10.9% and 11.5%, respectively. The predictive values for lethality of Fine pneumonia severity index and CURB-65 (Confusion, Urea nitrogen, Respiratory rate, Blood pressure, 65 years of age and older) had an area under the ROC curve of 0.8 and 0.69, respectively. Multivariate analysis disclosed blood urea nitrogen over 30 mg/ dL (odds ratio (OR), 6.8), need for mechanical ventilation (OR, 7.4) and diastolic blood pressure below 50 mmHg (OR, 3.9), as significant independent predictors of death. CONCLUSIONS: Pneumococcal pneumonia was associated with a substantial rate of complications and mortality. Clinical presentation and outcome did not differ significantly among patients with and without bacteremia.

[Nutritional status in the pediatric population of a rural area on the Ecuadorian coast]. / Estudio del estado nutricional de la población infantil de la zona rural de la costa ecuatoriana.

OBJECTIVES: To determine the effects of a diet based on carbohydrates on the nutritional status of a pediatric population through a study performed in a rural area of the province of Los Ríos (Ecuador). PATIENTS AND METHODS: We evaluated 871 Ecuadorian children from a rural environment in an ambulatory medical clinic created for the purposes of the study. Basic anthropometric measurements (weigh, height, head circumference and upper arm circumference) and clinical data from physical examination were recorded. The anthropometric measurements were compared with the growth charts used in Spanish children, which were taken as the standard reference measurements. Information on nutrition was obtained from interviews with the mothers. RESULTS: A total of 871 children were evaluated (53 % boys; 47 % girls). Mean age was 6.39 years (range: 0-14 years; mode 4). Comparison of the data obtained with the standard growth charts for the Spanish pediatric population revealed significant differences in body mass index in boys aged 5-14 years and in girls aged 3-12 years and highly significant differences in boys aged 6-13 years and in girls aged 3-12 years. Significant differences in middle upper arm circumference were found in boys and girls aged 1-14 years and highly significant differences were found in boys aged 1-12 years and in girls aged 2-12 years. A middle upper arm circumference of less than 14 cm (slight malnutrition) was found in 6.67 % of boys and in 9.15 % of girls; a middle upper arm circumference of less than 12.5 cm (serious malnutrition) was found in 1.82 % of boys and in 2.82 % of girls. Nutritional interviews revealed that the overall caloric intake was approximately 1,500 cal/ day. Eight percent of calories came from carbohydrates, 15 % from fats and 5 % from proteins. CONCLUSIONS: A poor diet affects the child population's nutritional status qualitatively but not quantitatively. Nutritional deficit favors the prevalence of childhood diseases that could be avoided by suitable feeding and hygiene. Because of the lack of economic and health resources, prevention is the fundamental weapon for maintaining health in underdeveloped countries. Childhood nutritional status is influenced by diet, which in turn is influenced by physical, climatic, cultural and political factors, and by stress, which is provoked by infections and parents' behavior. Nutritional status in children is a clear reflection of the socioeconomic status of a given population.

Reactions of 1-tosyl-3-substituted indoles with conjugated dienes under thermal and/or high-pressure conditions.

The behavior of 1-tosyl-3-acetylindole (1a), N,N-diethyl-1-tosyl-3-indoleglyoxylamide (1b), and 1-tosyl-3-nitroindole (1c) as dienophiles in Diels-Alder reactions under thermal and/or high-pressure conditions was explored with different dienes: isoprene (2), 1-(N-acetyl-N-propylamino)-1,3-butadiene (3), and 1-methoxy-3-trimethylsilyloxy-1,3-butadiene (Danishefsky's diene) (4). Compared to the acylated indoles, the nitro derivative proved to be the best dienophile. In general, the use of Danishefsky's diene led to high-yielding reactions under milder conditions. Likewise, high-pressure conditions proved to be better in producing high yields of products. The advantage of high-pressure over thermal conditions was the ability of the former to generate highly functionalized adducts in better yields, which were otherwise very difficult or impossible to obtain. The use of thermal or high-pressure conditions led to different regio- and/or stereoselectivity in the adducts, allowing control of the regio- or stereoisomer produced.

Vectorial importance of triatominae bugs (Hemiptera: Reduviidae) in Guaymas, Mexico.

The study was conducted in Guaymas city, Sonora, in Northwestern Mexico. Triatomines were collected manually during daytime, within and around houses selected randomly, with one person searching for bugs during one hour per house. Collected bugs were identified and analyzed for Trypanosoma cruzi infection. From a total of 279 collected specimens there were 123 females, 65 males and 91 nymphs (entomological indexes: 63% infestation, 68.4% colonization, 8.5% density and 13.5% stacking). There were 251 (90%) triatominae bugs infected with T. cruzi, one of the highest natural infestation levels recorded in Mexico. The insects collected were identified as Triatoma rubida (91%) and T. recurva (9%). Previous reports for the same locality (1959) indicated the presence of T. rubida in the wild, we found T. rubida within houses, and T. recurva as a peridomestic bug. Unplanned housing developments in originally wild areas may have favored T. cruzi transmitters to migrate from the wild and into human dwellings.

Common occurrence of concurrent infections by multiple dengue virus serotypes.

The co-circulation of all 4 dengue virus serotypes in the same community, common since the 1950s in Southeast Asia, has now become a frequent occurrence in many Caribbean Islands, Mexico, and Central and South America in the past 20 years. As a consequence, the frequency of concurrent infections would be expected to increase in these areas. To assess this, using state of the art technology, we screened viremic serum samples and mosquitoes inoculated with serum samples collected during epidemics involving multiple dengue virus serotypes in Indonesia, Mexico, and Puerto Rico for virus isolation. Of 292 samples tested, 16 (5.5%) were found to contain 2 or more dengue viruses by an indirect immunofluorescence test and/or the reverse transcriptase-polymerase chain reaction.

Opioid availability in Latin America: the Santo Domingo report progress since the Declaration of Florianopolis.

The World Health Organization (WHO) has indicated that opioid analgesics are insufficiently available, particularly in developing countries, due to a variety of reasons, including legislative, educational, and policy issues. In its effort to promote the rational use of medical opioids and the adequate treatment of patients with cancer, WHO has sponsored a meeting of Latin American representatives every 2 years, which includes health professionals and government regulators. During March 24-27, 1996, a group of 86 representatives of cancer pain relief and palliative care programs from nine Latin American countries met in Santo Domingo under the auspices of the WHO Palliative Care Program for Latin America. For the first time since the First Latin American Meeting, government regulators were present to help address the issue of opioid availability from their perspective. During the meeting, issues pertaining to cancer pain, opioid availability, and palliative care were discussed. This report summarizes some of the events and presents a summary of the conclusions of an earlier meeting in 1994, as described in the Declaration of Florianopolis, and presents its follow-up, The Santo Domingo Report, generated following the 1996 meeting.

Cholera in Lima, Peru, correlates with prior isolation of Vibrio cholerae from the environment.

The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 10(2)/ml to 10(5)/ml, with the highest counts in sewage-contaminated areas and irrigation water. With our methodology, no V. cholerae cases were detected at any site during the winter months of July through October. Counts were detectable in the environment before onset of cholera in the community, with counts at "cleaner" sites upriver correlating significantly with occurrence of community disease 2 and 3 months later. In sites with heavy sewage contamination, V. cholerae could still be detected before the onset of cases in the community; however, in contrast to upriver sites, counts at these latter sites correlated most closely with the number of concurrently occurring cholera cases. These data support a model of cholera seasonality in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds.

PIP: A newly developed DNA probe technique was used to analyze the occurrence of Vibrio cholerae in samples collected from 12 environmental sites in metropolitan Lima, Peru, each month from November 1993 to March 1995. Epidemic V. cholerae cases were found in 69 (34.5%) of the 200 samples collected. This represents more than twice the number of cholera-positive samples correctly identified with traditional methods. The highest V. cholerae counts were recorded in sewage-contaminated areas and irrigation water. No V. cholerae cases were detected at any site during the winter months of July through October. At the relatively cleaner upriver sites, counts were detectable 2-3 months prior to the outbreak of disease in the community. In sites with heavy sewage contamination, counts were more closely correlated with the number of concurrently occurring cholera cases in the community. These findings provide evidence for a model of cholera seasonality, in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by an onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds. Enhanced understanding of the complex web of human and environmental interactions that lead to seasonal cholera outbreaks would facilitate the design of preventive interventions.