[Human bocavirus in Chile: clinical characteristics and epidemiological profile in children with acute respiratory tract infections]

BACKGROUND

Human bocavirus (HBoV) is a newly discovered parvovirus found in children with acute respiratory tract infections (ARTI).

OBJECTIVES

To describe the epidemiological and clinical profile of children < 5 years old consulting for ARTI, comparing cases of HBoV monoinfection and coinfection with other known respiratory viruses. Furthermore, we aimed to estimate the prevalence of viral shedding in asymptomatic children and perform phylogenetic analysis.

PATIENTS AND METHODS

We investigated the presence of HBoV in nasopharyngeal secretions from children consulting for AlRTI and among asymptomatic controls, between 2007 and 2008, by polymerase chain reaction.

RESULTS

HBoV was detected in 79 (21.8%) of 362 nasopharyngeal swabs obtained from children with ARTI. In 60/79 (76%), coinfection with other respiratory viruses was confirmed. Most common symptoms were cough, fever and rhinorrhea. Children infected only with HBoV showed significantly lower frequencies of respiratory distress, oxygen requirements and hospital admission than those with coinfection. HBoV was detected in 6/16 (37.5%) samples from asymptomatic children. The phylogenetic analysis of viruses from Chilean patients revealed that circulating HBoV was closely related to original strains.

CONCLUSIONS

HBoV was found either in symptomatic and asymptomatic children. The severity of the disease was greater when HBoV was associated to other respiratory viruses.

[Pandemic influenza one year after the first wave: what did we learn?]

During year 2009 our nation experimented the first influenza pandemic wave due to the novel influenza A (H1N1) 2009 virus that emerged in the Northern hemisphere at the end of April, 2009. Estimated attack rate was about 6 to 12% affecting mainly to schoolchildren who presented with a mild disease. Age groups with highest risk of hospitalization were elderly people and children under 5 years old. Elderly patients and patients with co-morbidities had the highest risk to die. We have learned that clinical diagnosis of influenza has a laboratory confirmation in about 80% of cases but its correlation is lower in kids under 5 years old, especially in infants when RSV co-circulates with influenza virus. Laboratory diagnostic methods like DFA and immuno-chromatography have about 80% of sensitivity but a significantly lower rate in elderly patients compared to PCR. The clinical impact of this new virus justifies the recommendation to vaccinate traditionally established risk groups and to prescribe antiviral treatment to patients that acquire severe influenza or have risk factors to progress to complications.

[Seroepidemiological evidence of human exposure to Anaplasma sp in Santiago, Chile]

OBJECTIVES AND METHODS

To find more evidence of human exposure to Anaplasma sp in Chile, we studied 108 contacts of dogs with canine ehrlichiosis (CE) (risk group) and 61 persons without tick or CE cases contact (control group). A survey including risk factors and history of diseases compatible with ehrlichiosis/ anaplasmosis was applied to the risk group. Serum IgG anti-Anaplasma sp antibodies were determined in both groups.

RESULTS

A significant difference was found in the prevalence of anti-Anaplasma sp antibodies in the risk group compared with the control group (18,5 versus 3,3%), p < 0,005. No risk factors associated to seropositivity were found, nor persons with history suggesting ehrlichiosis/anaplasmosis. Ninety four percent of the houses of the risk group had tick infestation.

DISCUSSION

A greater risk of exposition to Anaplasma sp is documented in people living in close contact with CE cases and in houses with tick infestation.

[Disseminated and fatal adenovirus infection in an immunocompromised child]

Severe adenovirus (ADV) infections have become increasingly important in immunocompromised patients, mainly in pediatric stem cell transplant recipients. We report a case of disseminated ADV infection leading to death in a 12-year-old stem cell transplant recipient. The diagnosis was confirmed by viral isolation and viral genome detection in tissues and blood. Main issues associated with infection, diagnosis and therapeutic alternatives are reviewed. This case should alert clinicians to suspect and study this agent in high risk patients and highlights the importance of having antiviral drugs for ADV available in Chile.

[Human metapneumovirus as hospitalization cause in children under 3 years old with acute respiratory infections during 2004]

Human metapneumovirus was detected in 15 of 123 children (12%) younger than 3 years of age hospitalized for treatment of acute respiratory infection between July and November 2004. The virus was detected by RT-PCR directly from nasopharyngeal swabs and/or from supernatants after cell culture. Children infected with hMPV were mostly younger than one year of age (67%), all presenting with fever and cough. The main cause for hospitalization was the need for oxygen therapy (73%). Four hMPV positive children had an identifiable co-morbid condition but had a similar clinical evolution when compared to previously healthy infants. Chest radiography showed an increase in interstitial infiltrates with focal consolidation in 6 children. Obstructive bronchial syndrome and bronchiolitis, with or without pneumonia, were the most frequent diagnosis associated with hMPV positivity. A rapid and sensitive diagnostic method is required to improve diagnosis and treatment of these patients.

Vacuna anti-pertussis para uso en adolescentes y adultos

After the introduction of the pertussis vaccine the number of cases decreased substantially, albeit, the disease remains present affecting mostly young infants in whom it causes severe complications, adolescents and adults. Adults are the main reservoir of Bordetella pertussis and serve as vehicle of transmission reservoir to infants. The new pertussis vaccines, manufactured for adolescents and adults, have good immunogenicity, safety and efficacy (92%) profile. The introduction of this vaccine into a universal vaccination program for adolescents and adults, would decrease the incidence of the disease in this population and more importantly, transmission of the microorganism to infants.

Perfil clínico-epidemiológico de las infecciones por virus respiratorios en adultos hospitalizados durante la estación de influenza 2004

BACKGROUND

During yearly influenza (FLU) season, FLU viruses are well represented among hospitalized patients as in the community. Also, other respiratory viruses could be represented among adult in-patients.

AIM

to describe the presence and clinical- epidemiological characteristics of non-FLU respiratory virus infections (respiratory syncytial-RSV, parainfluenza and adenovirus-ADV) among hospitalized adults during FLU season and to compare with FLU-A (IA) or -B (IB) cases.

PATIENTS AND METHODS

Adult patients hospitalized at Hospital Clínico Universidad Católica between May to July 2004 with a respiratory virus infections confirmed by rapid antigen test or direct immunofluorescence of IA, IB (Flu group) or RSV, parainfluenza (1-2-3) and ADV (non-Flu group) were included.

RESULTS

86 cases were identified: 73.5% FLU (48.2% IA, 25.3% IB) and 26.5% non-FLU (15.7% parainfluenza-2; 8.4% RSV; 1.2% parainfluenza-3; 1.2% ADV). No differences were observed in general characteristics and evolution of patients. In FLU-group were more frequently observed myalgia, cough, hospitalization due to febrile syndrome, higher values of C-reactive protein and band leukocytes count (p < 0.05).

CONCLUSIONS

During 2004 FLU season a 26.5 % of respiratory viral infection were due to non-FLU viruses among adult hospitalized in our centre. The difficulty to difference FLU vs. non-FLU infections, suggest that it is necessary to include other respiratory virus in the viral etiological diagnosis, even in FLU season.

[Malaria: report of 12 non autochthonous cases]

Malaria is a protozoan infection caused by four Plasmodia species transmitted by female Anopheles mosquito. Nearly 40% of the world population is at risk of acquiring the disease because of increasing resistance to treatment, climate changes and travels to endemic zones. We report twelve patients with diagnosis of malaria, supported by the identification of parasites on blood smear. All cases had traveled to endemic zones (Peru, Ecuador, Central America, Africa), but only three used chemoprophylaxis. Seven cases were infected with Plasmodium vivax and five cases with P. falciparum. Three of latter required intensive care. All patients were treated with standard drugs according to the severity and Plasmodium specie, with excellent results and no mortality.

[Guidelines for management of animal bites]

Bites caused by pets or free living animal, including the so called exotic ones are a common cause of medical care request, although its real dimension has not been well defined in the local setting. This paper reviews the epidemiology of the topic placing emphasis in the initial approach and recommendations for the management of dog and cat bites. Due to increasing ownership or contact with other animals, management of bites from hamsters, mice, ferrets, rabbits, prairie dogs, monkeys, bats, lizards and bird bites is also discussed.

[Risk factors and frequency of positive antibodies for leptospirosis in a sub urban population near Santiago]

BACKGROUND

Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place.

AIM

To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey.

MATERIAL AND METHODS

Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira.

RESULTS

Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected.

CONCLUSIONS

In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection.