One Health in Practice: A Pilot Project for Integrated Care of Zoonotic Infections in Immunocompromised Children and Their Pets in Chile.

Although pets provide physiological and psychological benefits to their owners, they are a potential source of zoonotic infections, especially for vulnerable individuals such as immunocompromised patients. During 1 year, we therefore performed a pilot project, which included 32 immunocompromised Chilean children and their family pets (35 dogs and 9 cats) with the aim of detecting, treating and preventing zoonotic infections. Children were examined by Infectious Diseases paediatricians and demographical and clinical information related to zoonotic infections were recorded. Pets were examined and sampled by veterinarians, who also administered missing routine vaccines and anti-parasitics. During family visits, all members were informed and educated about zoonoses and a satisfaction survey was performed. Visits also included vector control and indoor residual spraying with pyrethroids. Children were re-examined and re-tested according to the findings of their pets, and all detected zoonotic infections were treated both in children and pets. Physical examination revealed abnormalities in 18 dogs (51.4%) and three cats (33.3%). Twenty-eight (63.6%) of the pets were diagnosed with a zoonotic pathogen, and seven (15.9%) with a facultative pathogen. Most zoonotic agents were isolated from the pet's external ear and intestine. Bacteria with the highest pathogenic potential were Campylobacter jejuni and Brucella canis. In two children and their respective pets, the same zoonotic diseases were diagnosed (toxocariasis and giardiasis). Arthropods serving as potential vectors of zoonotic infections were found in 49% of dogs and 44% of cats. The pilot project was positively evaluated by the participating families. Our pilot project confirmed that pets are reservoir for various zoonotic agents in Chile and that the implementation of an integrated multidisciplinary programme was a valuable tool to prevent, diagnose and treat such zoonotic infections in vulnerable patients such as immunocompromised children.

Seroprevalence of parvovirus B19 in urban Chilean children and young adults, 1990 and 1996.

An immunofluorescence test for detecting parvovirus B19 IgG was developed by infecting insect cells with recombinant baculovirus expressing the capsid protein VPI. The test was used to study the prevalence of antibodies in 725 healthy children and young adults living in Santiago, Chile. In total, 248 sera were taken in 1990 and 477 in 1996. The seroprevalence was low in children less than 5 years old (3% in 1990 and 21% in 1996). It rose during school age to a prevalence around 50%, reaching 60% in young adults. No differences were found between genders. There was a statistically significant higher seroprevalence in the low socioeconomic status group in 1990 samples, but this was not observed in 1996. The higher prevalence observed in children less than 5 years of age in 1996 compared with 1990 could be explained by the occurrence of intervening epidemics of parvovirus B19 infection.

Vaccination against hepatitis A in children aged 12 to 24 months [corrected].

BACKGROUND: Current hepatitis A vaccines are either licensed for children >2 years of age, as in the U.S. or Chile, or >1 year of age, as in Europe and other parts of the world. Recent recommendations for immunization against hepatitis A have included routine vaccination of children in areas or regions of higher endemicity. However, data on hepatitis A vaccination in toddlers aged between 1 and 2 years are scarce. METHODS: This open clinical study investigated the reactogenicity and immunogenicity of two doses (0, 6-month schedule) of an inactivated hepatitis A vaccine (Havrix pediatric, Glaxco SmithKline Biologicals, Rixensart, Belgium) in 120 seronegative children aged 12-24 months. RESULTS: Pain at the injection site and irritability were the most frequently reported local and general symptoms, respectively. No serious adverse events related to the study vaccine were reported. One month after the first dose, all but one subject had antibodies against hepatitis A with a GMT of 159 mIU/mL. After the booster dose, all had antibodies with a GMT of 2,939 mIU/mL. CONCLUSIONS: Our data show that the inactivated hepatitis A vaccine was well tolerated by these toddlers and that the vaccine elicits a good immune response.

[Complications in children with varicella in 4 hospitals in Santiago, Chile: clinical spectrum and estimation of direct costs]. / Complicaciones en niños con varicela en cuatro hospitales de Santiago-Chile: espectro clínico y estimación de costos directos.

BACKGROUND: The knowledge of varicella complications and their associated cost may help for a better evaluation of varicella immunization benefits. AIM: To determine frequency, type, outcome and affected population of varicella complications in children requiring hospitalization, and to estimate their direct costs. MATERIAL AND METHODS: Retrospective analysis of medical records of children admitted to four hospitals in Santiago, Chile, due to varicella complications between January 1997 and February 1999. Calculation of direct costs of hospitalizations in a sample of 30 patients. RESULTS: One hundred fifty four patients were identified, 74% were younger than 5 years old, only one was immunocompromised. Complications identified were skin and soft tissue infections in 63%, invasive infections in 25.3%, neurological in 7.1% and miscellaneous in 4.5%. Staphylococcus aureus and Group A beta-haemolytic Streptococcus (GABS) were predominantly isolated. S. aureus was the main agent identified in superficial infections and GABS in invasive infections (sterile sites). Two patients died due to invasive infections (streptococcal toxic shock and S. aureus septicaemia) and 11 required surgical procedures. The average cost per hospitalization was US$ 600 in public hospitals and US$ 1,800 in the private hospital. CONCLUSIONS: Varicella complications requiring hospitalization are due mainly to bacterial infections and they affect immunocompetent toddlers. These complications can be severe and even fatal.

Regional lymphadenopathy in cat-scratch disease: ultrasonographic findings.

BACKGROUND: Cat-scratch disease (CSD) is considered to be an emerging disease worldwide and is caused by Bartonella henselae, a gram-negative bacterium introduced by a scratch or bite of a cat. The most common clinical manifestation is regional lymphadenopathy, but clinical recognition may be difficult, as atypical manifestations may occur. The diagnosis is confirmed with serologic testing and histology is rarely needed. This paper is based on our experience with the use of ultrasonography in the diagnosis of CSD. OBJECTIVE: The aim of this study was to describe the sonographic and color Doppler appearances of regional lymphadenopathy in CSD, as this has not widely reported in the literature. MATERIALS AND METHODS: Forty-seven patients (average 9.4 years) were included who all had serologically and/or histologically proven CSD and had been studied using US early in the clinical course. All had a positive history of exposure to cats and exhibited regional lymphadenopathy. RESULTS: US showed large hypoechoic adenopathy with some transmission enhancement and high vascularization on color-flow Doppler imaging. In 30 patients, abdominal US was also performed and splenic and/or hepatic granulomata were found in 10. CONCLUSIONS: In our experience, sonography and especially color-Doppler and power-Doppler sonography was helpful in the diagnosis of CSD. We believe it should be used in the initial study of children with regional lymphadenopathy, and serologic testing should be performed when CSD is suspected.

[Molecular epidemiology of the human immunodeficiency virus type 1 in Santiago, Chile]. / Epidemiología molecular del virus de inmunodeficiencia humana tipo 1 en Santiago, Chile.

BACKGROUND: Most of the studies of HIV-1 infection in South America have been limited to Brazil and little is known about the viral variants that are causing disease elsewhere in the continent. AIM: To determine the characteristics of the viral variants present in Chile as well as patterns of viral transmission. MATERIAL AND METHODS: Viral sequences were obtained from 21 HIV-1 infected people from Santiago, Chile who were infected either via sexual contact or intravenous drug use. Cloned sequences obtained from both the third variable and conserved regions of the envelope as well as the viral protease were evaluated. RESULTS: We found only clade B subtype viruses in Santiago. An evaluation of the envelope gene revealed no evidence that the sequences were monophyletic by risk group. A number of the protease sequences were predicted to encode amino acid substitutions commonly found during selection for protease inhibitor resistance. CONCLUSIONS: The HIV-1 strains studied in Chile, belong to the subtype B. There is no molecular evidence of separate introductions of the virus into the different risk groups. A number of substitutions in the protease gene that may confer resistance to protease inhibitors were found in patients with no previous exposure to this class of drugs.

[Resistance of human immunodeficiency virus (HIV) to zidovudine. Genotypic analysis in strains isolated from Chilean patients]. / Resistencia del virus de inmunodeficiencia humano (VIH) a zidovudina (AZT): análisis genotípico en cepas aisladas de pacientes chilenos.

BACKGROUND: Resistance of HIV to AZT is the result of mutations in the pol gene that codifies the enzyme reverse transcriptase. AIM: To assess the resistance to antiretroviral drugs in Chilean patients infected with HIV. MATERIAL AND METHODS: The presence of mutations was searched in 22 patients infected with HIV. The emergence or persistence of these mutations was studied in sequential samples of 19 patients. The presence of the mutation that confers resistance to didanosine (DDI) was studied in those subjects exposed to the drug. Polymerase chain reaction techniques were used to analyze mutations in codons 41, 70 and 215 of the pol gene (resistance to AZT) and the mutation in codon 71 (resistance to DDI). RESULTS: On admission, none of the patients without previous exposure to AZT had drug resistance mutations. Seven of 12 patients (58.3%) that had received AZT had mutations in codon 215. In two, they were associated to a mutation in codon 41 and in two, a mutation in codon 70. After a mean follow up of 14 months, 13 of 15 patients (86%) that received AZT had viral strains genotypically resistant to the drug. In nine of these, the resistance was associated with disease progression. None of the 10 patients that received DDI had the mutation in codon 74 that confers resistance to the drug. However, in one of these patients, that never received AZT, a virus with a mutation in codon 215 was detected. CONCLUSIONS: A high percentage of patients that have received monotherapy with AZT have genotypic resistance to the drug. This resistance is associated with clinical and immunological derangement in 70% of these subjects.

[Seroprevalence of cytomegalovirus and Toxoplasma gondii in healthy subjects under 30 years old in Santiago, Chile]. / Seroprevalencia de citomegalovirus y Toxoplasma gondii en población sana menor de 30 años, en Santiago de Chile.

BACKGROUND: Infections by Cytomegalovirus and Toxoplasma gondii are endemic in Chile and only a low proportion of infected individuals have clinical manifestations. AIM: To study the prevalence of infection by Cytomegalovirus and Toxoplasma gondii in Chile. SUBJECTS AND METHODS: The prevalence of IgG antibodies against Cytomegalovirus and Toxoplasma gondii were studied in 560 subjects under 30 years old, using an ELISA technique. Age, socioeconomic level, breast feeding, assistance to nurseries and number of family members were considered as risk factors for these infections. RESULTS: Infection by Cytomegalovirus had a global prevalence of 60%. It showed an epidemiological pattern of late acquisition in high socioeconomic levels and a pattern of early infection in medium and low socioeconomic levels. Eighty to 90% of sera were positive for the infection in adult subjects of the three socioeconomic levels. There was a positive correlation between the duration of breast feeding and the frequency of Cytomegalovirus infection. Infection by Toxoplasma gondii had a global prevalence of 24.6%. The rates of susceptible individuals were 80 and 50% in high and medium-low socioeconomic levels respectively. CONCLUSIONS: The knowledge about the frequency of these infections in high risk populations such as women during their reproductive years and immunodepressed individuals, will allow the implementation of preventive measures.

[Bartonella henselae infection in immunocompetent patients: cat scratch disease]. / Infección por Bartonella henselae en pacientes inmunocompetentes: enfermedad por arañazo de gato.

BACKGROUND: Cat scratch disease, whose etiologic agent is Bartonella henselae, is a benign disease in immunocompetent subjects, characterized by lymphadenopathy of prolonged course and occasional involvement of other organs such as liver, spleen, central nervous system, eye and lung. In immunocompromised patients, the infection is bacteremic and disseminated. AIM: To report Chilean cases of cat scratch disease. PATIENTS AND METHODS: Ten children (seven male, aged between 6 and 13 years old) with histologically or serologically confirmed cat scratch disease are reported. RESULTS: Lymphadenopathy location was pre auricular in four cases, axillary in two, inguinal in two and epitrochlear in two. Three children had fever over 39 degrees C and two had a parinaud syndrome. Nine children had a history of cat scratch and one of a cat byte. Six had an erythrocyte sedimentation rate over 40. Lymph node ultrasound examination was a useful diagnostic tool. Two patients had splenic granulomas. Lymph node biopsies were obtained in four cases, showing a suppurative granulomatous lymphadenitis in all and a positive Warthin-Starry stain in two. Serology, done in patients without histological confirmation was positive with titles ranging from 1:64 to 1:8192. All patients had a satisfactory outcome with regression of lymphadenopathy. CONCLUSIONS: Infections by Bartonella hemselae occur in the Chilean population and must be considered in the differential diagnosis of regional lymph node enlargement.

[Neuroborreliosis in Chile. Report of a child probably infected by imported pets]. / Neuroborreliosis en Chile. Caso pediátrico de probable adquisición por mascotas importadas.

Lyme disease, caused by the spirochete Borrelia burgdorferi, has several clinical manifestations and is transmitted to man by tick bites. In Chile and Latin America, several cases have been reported, but none with immunoblot confirmation or isolation of the infecting organism. We report a 9 year old boy consulting with bilateral facial palsy, polyradiculoneuritis with tetraparesis and meningeal irritation. Cerebrospinal fluid analysis showed increased protein concentration without pleocytosis and negative viral or bacterial cultures. IgM antibodies against Borrelia burgdorferi, were positive by ELISA and were confirmed by immunoblot at the Reference Laboratory of the University of Connecticut. The child had a recent contact with hamsters brought from Germany. The substantiation of Lyme disease existence in Chile should prompt the search and isolation of the causal agent.

[Natural history of human immunodeficiency virus infection in a cohort of Chilean patients]. / Historia natural de la infección por virus de inmunodeficiencia humano en una cohorte de pacientes chilenos.

We characterized clinical manifestations and the risk to develop AIDS in a cohort of 32 patients infected with human immunodeficiency virus without AIDS A multivariate analysis was performed to determine association between the progression of infection and control variables (socioeconomic level, age, sex and sexual preferences) and causal variables (psycho-social changes, significant clinical events, stress scoring and sexual activity). The cumulative AIDS incidence, defined as a CD4 lymphocyte count below 200 cells/cm3 was 50% at 6.5 years and 82% at 8 years. Using clinical criteria to define AIDS, 50% developed the disease at 8 years of follow up. Among studied factors, only age (faster progression at higher age) and time of evolution were associated with progression in stages before AIDS, the most frequent diseases were acute diarrhea, sexual transmission diseases, oral candidiasis, sinusitis and varicella zoster infections. The reduction; of CD4 lymphocytes-below 200 cells/cm3 always preceded the symptoms of the disease. Two patients have remained more than eight years without clinical or immunological deterioration.

PIP: Clinical manifestations and the risk of developing AIDS were studied in a cohort of 32 HIV-seropositive patients referred by their treating physicians to the Center for Medical Investigation of the Catholic University of Chile. The only exclusion criteria were a CD4 lymphocyte count below 400 or marked symptoms of AIDS. The study design included an examination at entry and every 6 months thereafter for a maximum follow up of 3 years. A multivariate analysis was conducted to determine the relation between disease progression and control and causal variables. The subjects were 8 women averaging 38 years old and 24 men averaging 33 years. Most were middle class and had higher education. 46% of the men became sexually active before age 15 and 42% were homosexual. HIV transmission was sexual in 28 subjects, through intravenous drug use in 2, and by unknown route in 2. The subjects had been infected for an average of 4.3 years at entry into the study. Of the 30 whose date of infection was known, 16 developed AIDS during the study according to the criterion of CD4 lymphocyte count below 200, and 8 of these developed markers of AIDS. 50% of patients developed AIDS 6.5 years after infection and 82% 8 years after. Using clinical criteria, 50% of patients had developed AIDS 8 years after infection. Multivariate analysis showed only subject's age at infection (faster progression at higher ages) and length of time since infection to be related to the risk of developing AIDS. No association was observed between development of the disease and sex, sexual orientation, use of alcohol or drugs, smoking, history of sexually transmitted diseases, number of sexual partners, or frequency of sexual relations. The most frequently observed pathologies before the stage of AIDS were acute diarrhea, sexually transmitted diseases, oral candidiasis, sinusitis, and varicela zoster infections. In the patients who progressed to AIDS, the decline of the CD4 lymphocyte count below 200 always preceded other symptoms. Two patients showed no significant decline in CD4 lymphocyte count or clinical manifestations of AIDS more than 8 years after infection.