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Biomedical subjects

R H Gilman

Publications and source records attributed to R H Gilman.

At least 37 records · Page 2Linked to original sources

Screening for sexually transmitted diseases in human immunodeficiency virus-positive patients in Peru reveals an absence of Chlamydia trachomatis and identifies Trichomonas vaginalis in pharyngeal specimens.

To determine the prevalence of sexually transmitted diseases (STDs), we screened 107 human immunodeficiency virus-positive patients in Peru, where the virus is predominantly sexually transmitted. Patients had multiple risk factors for STDs, and 38% of women and 50% of men had at least 1 STD (gonorrhea, trichomoniasis, herpes simplex, anogenital warts, or syphilis seropositivity). No chlamydial infection was detected, even though infection rates in the general population are 5%-12%. Patients receiving trimethoprim-sulfamethoxazole(TMP-SMZ) for prophylaxis or treatment of respiratory infections were least likely to have cervicitis and/or urethritis (odds ratio, 0.37; 95% confidence interval, 0.15-0.89). Although not optimal treatment, administration of TMP-SMZ is effective against chlamydial infection. We speculate that the use of concomitant medications, such as TMP-SMZ, may be inadvertently preventing chlamydial infection in this population. Another finding was the presence of Trichomonas vaginalis in pharyngeal specimens of 3 men with histories of orogenital activity. This has not been previously reported and requires further study.

Adolescent↗

Fasciolopsiasis: is it a controllable food-borne disease?

Fasciolopsiasis, endemic to the Orient and Southeast Asia, is a snail-transmitted, intestinal, food-borne parasitic zoonosis caused by a trematode, Fasciolopsis buski, which also infects farm pigs. Fasciolopsiasis remains a public health problem despite changes in eating habits, alterations in social and agricultural practices, health education, industrialization, and environmental alterations. The disease occurs focally and is most prevalent in school-age children. In foci of parasite transmission, the prevalence of infection in children ranges from 57% in mainland China to 25% in Taiwan and from 50% in Bangladesh and 60% in India to 10% in Thailand. Control programs implemented for food-borne zoonoses are not fully successful for fasciolopsiasis because of century-old traditions of eating raw aquatic plants and using untreated water. Fasciolopsiasis is aggravated by social and economic factors such as poverty, malnutrition, an explosively growing free-food market, a lack of sufficient food inspection and sanitation, other helminthiases, and declining economic conditions.

Adolescent↗

Sequence variation in the cytochrome oxidase I, internal transcribed spacer 1, and Ts14 diagnostic antigen sequences of Taenia solium isolates from South and Central America, India, and Asia.

We examined the genetic variability in the pig-human tapeworm, Taenia solium, by sequencing the genes for cytochrome oxidase I, internal transcribed spacer 1, and a diagnostic antigen, Ts14, from individual cysts isolated from Peru, Colombia, Mexico, India, China, and the Philippines. For these genes, the rate of nucleotide variation was minimal. Isolates from these countries can be distinguished based on one to eight nucleotide differences in the 396 nucleotide cytochrome oxidase I (COI) sequence. However, all of the 15 isolates from within Peru had identical COI sequences. The Ts14 sequences from India and China were identical and differed from the Peru sequence by three nucleotides in 333. These data indicate that there is minimal genetic variability within the species T. solium. Minimal variability was also seen in the ITS1 sequence, but this variation was observed within the individual. Twenty-two cloned sequences from six isolates sorted into 13 unique sequences. The variability observed within the sequences from individual cysts was as great as the variability between the isolates.

Animals↗

Failure of one-day praziquantel treatment in patients with multiple neurocysticercosis lesions.

A recently described one-day regimen of praziquantel (PZQ) therapy for neurocysticercosis (NCC), three doses of 25 mg/k given at 2 h intervals, was applied in eight patients with viable NCC cysts without any evidence of inflammation. Resolution of lesions in computed tomography (CT) was observed in all five patients with a single cyst, whereas all cysts survived in three patients with multiple brain parasites. One-day praziquantel is a good regimen for patients with a single viable brain cysticercus but is poorly effective for multiple cysts.

Adult↗

The role of non-biting flies in the epidemiology of human infectious diseases.

The feeding and reproductive habits of non-biting synanthropic flies make them important mechanical vectors of human pathogens. Synanthropic flies are major epidemiologic factors responsible for the spread of acute gastroenteritis and trachoma among infants and young children in (predominantly) developing countries. House flies are involved in mechanical transmission of nosocomial infections with multiple antibiotic-resistant bacteria in hospital environments.

Acute Disease↗

Posttreatment follow-up of Helicobacter pylori infection using a stool antigen immunoassay.

The Helicobacter pylori stool antigen enzyme immunoassay (HpSA) was evaluated during posttreatment follow-up of patients in a country with a very high prevalence of H. pylori infection. From among 273 dyspeptic individuals (18 to 55 years) initially recruited from a shantytown in Lima, Peru, 238 participants who met the inclusion criteria and were suspected to be H. pylori positive based on (14)C urea breath test (UBT) results underwent endoscopy. Participants with endoscopy-proven infections received standard eradication therapy and were monitored by UBT and HpSA at 1 month following treatment and at 3-month intervals for 9 months posttreatment. A second endoscopy was performed if UBT results showed evidence of treatment failure or H. pylori recurrence. Biopsy results were considered the "gold standard" in all analyses. Among patients who underwent endoscopy, HpSA had a pretreatment sensitivity of 93%. Two-hundred thirty patients completed the treatment regimen, of whom 201 (93%) were considered to have had successful treatment outcomes based on a negative follow-up UBT. Thirty-two patients with UBT-defined treatment failures or H. pylori recurrences at any point during the 9-month follow-up underwent a second endoscopy. In the posttreatment setting, HpSA had an overall sensitivity of 73% and a specificity of 67%. Agreement between UBT and HpSA diminished throughout the follow-up. Among 14 participants in whom HpSA remained positive at 1 month following treatment despite UBT evidence of treatment success, 12 (86%) became HpSA negative within 3 months posttreatment. Although this study confirmed the validity of the HpSA in the initial assessment of dyspeptic patients, the test demonstrated a reduced overall accuracy in the detection of treatment failures and H. pylori recurrences during 9 months of posttreatment follow-up. Furthermore, in some patients it may take up to 3 months after successful eradication for antigen shedding to diminish to levels within the negative HpSA range.

Adolescent↗

Pulmonary tuberculosis in children in a developing country.

OBJECTIVE: We evaluated the clinical and epidemiologic characteristics of Peruvian children presenting with pulmonary tuberculosis (PTB) to determine whether features predictive of confirmed PTB could be identified. STUDY DESIGN: This was a cross-sectional study of 135 children (mean age: 6.8 years) presenting to the Hospital del Niño in Lima, Peru, with presumptive diagnosis of PTB. Clinical, epidemiologic, and laboratory findings were compared between 3 groups of pediatric patients with a presumptive diagnosis of PTB: those with positive Mycobacterium tuberculosis (MTB) cultures, those likely to have PTB based on clinical criteria but with negative cultures, and those who did not meet clinical diagnostic criteria or have positive cultures. RESULTS: A total of 50 (37%) patients were diagnosed with definitive PTB based on positive sputum culture. Another 55 (47%) patients were classified as having probable PTB based on meeting at least 2 of the following criteria: cough lasting for at least 2 weeks, typical chest radiograph changes, purified protein derivative (PPD) >/=10 mm, or history of tuberculosis family contact. Patients with definitive or probable PTB were significantly older than patients without clinical PTB, and those with symptomatic disease were significantly older than those with asymptomatic disease. Patients with PTB diagnosed by culture were significantly more likely than those diagnosed using clinical criteria to have cough lasting >/=2 weeks, fever, and a PPD >/=10 mm. CONCLUSIONS: The typical presentation of PTB in Peruvian children includes symptoms of active pulmonary disease similar to those seen in adults. This presentation differs significantly from that reported in developed countries, where many children have minimal or no symptoms at the time of presentation. The diagnostic criteria for pediatric PTB must be modified in hyperendemic developing country environments where features may differ from those described in the United States. The triad of cough lasting >/=2 weeks, fever, and a PPD >/=10 mm was highly predictive for culture-positive PTB among children in this low-income Peruvian population.

Age Factors↗

Acute Helicobacter pylori infection is followed by an increase in diarrheal disease among Peruvian children.

BACKGROUND: Cohort and case-crossover studies were conducted to evaluate whether new Helicobacter pylori infections are followed by increased diarrhea. METHODS: Participants were 6-month-old to 12-year-old shantytown residents living near Lima, Peru. Baseline data were collected from community households. Health interviews were completed daily, and sera, drawn every 4 months, were tested for H pylori immunoglobulin G. Diarrhea rates among newly H pylori-infected (seroconverting) children were compared with rates among persistently uninfected and infected children using cohort and case-crossover analyses. RESULTS: Sera were obtained from 345 children from January 1, 1995, through September 1, 1997. H pylori incidence was 12% per year (36 H pylori infections in 109 866 seronegative days). In adjusted cohort analyses, seroconverters had more diarrhea days (rate ratio: 2.0; 95% confidence interval: 1.6-2.4), episodes, and sick days in the year after infection than did uninfected children; and more diarrhea days and sick days than did persistently infected children. This effect was strongest in the first 2 months. Case-crossover analyses supported these findings. CONCLUSION: Preventing H pylori infection may help reduce pediatric diarrheal disease.

Acute Disease↗

Protection of pigs with cysticercosis from further infections after treatment with oxfendazole.

Cysticercosis, the infection by the larvae of Taenia solium, is a major cause of acquired epilepsy in the world; it also causes significant economic loss because of contaminated pork. This disease is endemic in most developing countries and no control strategy has yet been proven efficient and sustainable. To further evaluate the full potential of single-dose oxfendazole treatment for pigs as a control measure, 20 pigs with cysticercosis were treated with oxfendazole and later matched with 41 naive pigs and exposed to a natural challenge in a hyperendemic area. New infections were found by serologic testing in 15 of the 32 controls (47%), and by the presence of cysts at necropsy in 12 of them (37%). Only minute residual scars were detected in the carcasses of oxfendazole-treated pigs. Pigs with cysticercosis, once treated with oxfendazole, are protected from new infections for at least three months.

Animals↗

Short report: transient antibody response in Taenia solium infection in field conditions-a major contributor to high seroprevalence.

The discordance between extremely high seroprevalence of Taenia solium antibodies in disease-endemic populations, relatively few symptomatic cases of neurocysticercosis, and high background levels of putatively inactive brain lesions (mainly calcifications) in seronegative controls have confused researchers, clinicians, and epidemiologists in the last decade. We reviewed longitudinal serologic data from general population serosurveys in 3 different disease-endemic areas of Peru and Colombia and found that approximately 40% of seropositive people were seronegative when resampled after 1 year (3 surveys) or after 3 years (1 survey). Transient antibodies may have significant implications for the epidemiology of and immunity to this disease.

Animals↗

Experimental infection model for Taenia solium cysticercosis in swine. Cysticercosis Working Group in Peru.

A novel method for infecting pigs with Taenia solium using an intramuscular innoculum of oncospheres was investigated in a series of five experiments in 18 animals. The model is simple to perform, requires a minimal number of oncospheres, permits multiple infections per animal, and decreases the variation inherent in oral infection models. This intramuscular oncosphere assay (IMOA) may provide a valuable tool to evaluate therapeutic agents or potential vaccines for cysticercosis.

Administration, Oral↗

Identification of 5 types of Cryptosporidium parasites in children in Lima, Peru.

Cryptosporidium parvum is usually considered to be the pathogen responsible for human cryptosporidiosis. We genotyped Cryptosporidium in 132 stool specimens from 80 Peruvian children, representing 85 infection episodes, using techniques that differentiate Cryptosporidium species and C. parvum genotypes. Five types of Cryptosporidium were identified: C. parvum human (67), bovine (8), and dog (2) genotypes, C. meleagridis (7), and C. felis (1). Twenty-five (29%) of the 85 infection episodes were associated with diarrhea. There was no significant difference in age, antecedent stunting, percentage with diarrhea, or duration of diarrhea for episodes with human genotype, compared with those of zoonotic Cryptosporidium. Duration of oocyst shedding was longer for human genotype than for zoonotic Cryptosporidium (mean, 13.9 days and 6.4 days, respectively; P=.004). Serum samples from 8 children with C. meleagridis, C. felis, or C. parvum dog genotype were tested for anti-human immunodeficiency virus (HIV) type 1 antibodies; all were found to be negative. Contrary to common belief, novel Cryptosporidium species and C. parvum genotypes can infect HIV-negative children.

Animals↗

Natural history of infection with Bartonella bacilliformis in a nonendemic population.

An investigation was performed after an outbreak of bartonellosis in a region of Peru nonendemic for this disorder. Symptoms of acute and chronic bartonellosis were recorded. Serological analysis was performed on 55% of the affected population (554 individuals), 77.5% of whom demonstrated previous infection with Bartonella bacilliformis. The attack rate of Oroya fever was 13.8% (123 cases); the case-fatality rate was 0.7%. The attack rate of verruga peruana was 17.6%. A new specific immunostain was developed and used to confirm the presence of B. bacilliformis in the biopsied skin lesions. Most seropositive individuals (56%) were asymptomatic. The symptoms that were associated with prior infection, as determined by Western blot, included fever (37.2% of the seropositive vs. 17.2% of the seronegative population; P<.001), bone and joint pain (27% vs. 9%; P<.001), headache (27% vs. 12.3%; P <.001), and skin lesions described as verruga peruana (26.8% vs. 4.9%; P<.001). Our findings suggest that infection with B. bacilliformis causes a broad spectrum of disease that is significantly milder in severity than that frequently reported.

Adolescent↗

Effect of El Niño and ambient temperature on hospital admissions for diarrhoeal diseases in Peruvian children.

INTRODUCTION: To investigate whether the El Niño phenomenon and ambient temperature had an effect on the epidemiology of childhood diarrhoea, we analysed data on daily number of admissions of children with diarrhoea to the Oral Rehydration Unit of the Instituto de Salud del Niño in Lima, Peru, between January, 1993, and November, 1998. METHODS: We obtained daily data on hospital admissions from the Oral Rehydration Unit, and meteorological data from the Peruvian Weather Service, and used time-series linear regression models to assess the effects of the 1997-98 El Niño event on admissions for diarrhoea. FINDINGS: 57,331 children under 10 years old were admitted to the unit during the study. During the 1997-98 El Niño episode, mean ambient temperature in Lima increased up to 5 degrees C above normal, and the number of daily admissions for diarrhoea increased to 200% of the previous rate. 6225 excess admissions were attributable to El Niño, and these cost US$277,000. During the period before the El Niño episode, admissions for diarrhoea increased by 8% per 1 degree C increase in mean ambient temperature. The effects of El Niño and ambient temperature on the number of admissions for diarrhoea were greatest during the winter months. INTERPRETATION: El Niño had an effect on hospital admissions greater than that explained by the regular seasonal variability in ambient temperature. The excess increase in ambient temperature was the main environmental variable affecting admissions. If our findings are reproducible in other regions, diarrhoeal diseases may increase by millions of cases worldwide with each degree of increase in ambient temperature above normal.

Child↗

Development of Fasciolopsis buski (Trematoda : Fasciolidae) in Hippeutis umbilicalis and Segmentina trochoideus (Gastropoda : Pulmonata).

Sequential development and histopathologic effects of Fasciolopsis buski larvae were examined in two species of pulmonate snail, Hippeutis umbilicalis and Segmentina trochoideus. Miracidial attachment and penetration began 5 min post-exposure (PE). On day 2 PE, the sporocysts rapidly increased in size and over days 3-7 PE, they transformed into mother rediae which migrated to the ovotestis on day 10 PE. In both species of snail, daughter rediae were initially observed on day 17 PE, the first cercariae emerged on day 21 PE, and from that day onward daughter rediae were the dominant larval form occupying the ovotestis. Histopathologic changes were confined exclusively to the ovotestis and included lytic lesions due to mechanical damage, and disappearance of all cellular elements. No inflammatory responses were observed in the ovotestis, and no degenerated larvae of any kind were observed in the snails. Infected snails did not produce egg masses and lived no longer than 35 days. The lack of differences in miracidial recognition and penetration, and in the temporal, sequential, and spatial development of F. buski larvae in H. umbilicalis and S. trochoideus indicate that both these snail species are equally susceptible to F. buski.

Animals↗

Short regimen of praziquantel in the treatment of single brain enhancing lesions.

Twenty-six patients with single enhancing brain lesion (SEL) were openly assigned to receive single-day praziquantel therapy (n=14), or not (n=12). From 14 treated patients, complete resolution was found in 11, partial resolution in two, and the remaining case was later diagnosed as an arteriovenous malformation. Side effects presented in only one patient and remitted in the same day with symptomatic treatment. Conversely, the lesions persisted unchanged in six of 12 patients in the non-treatment group. Untreated patients with persisting lesions were prescribed praziquantel treatment. After this, SELs disappeared in three cases, other diagnoses (brain tuberculoma and arteriovenous malformation) were made in two, and one was not evaluated. When analyzed in regard to the baseline serology, resolution of lesions on computed tomography was found in 13 (complete=12, partial=1) of 14 seropositive patients, whereas it only happened in six (complete=5, partial=1) of 12 seronegative patients. Serological screening defines a subset of SEL patients with good prognosis. If antiparasitic therapy is to be used in patients with SEL, and we cannot find a strong argument against it, single-day praziquantel is the regimen of choice based on duration, costs, and minimal side effects.

Adolescent↗