Changes in tuberculosis epidemiology, United States, 1993-2017

BACKGROUND: After 20 years of steady decline, the pace of decline of tuberculosis (TB) incidence in the United States has slowed.METHODS: Trends in TB incidence rates and case counts since 1993 were assessed using national US surveillance data. Patient characteristics reported during 2014-2017 were compared with those for 2010-2013.RESULTS: TB rates and case counts slowed to an annual decline of respectively 2.2% (95%CI -3.4 to -1.0) and 1.5% (95%CI -2.7 to -0.3) since 2012, with decreases among US-born persons and no change among non-US-born persons. Overall, persons with TB diagnosed during 2014-2017 were older, more likely to have combined pulmonary and extra-pulmonary disease than extra-pulmonary disease alone, more likely to be of non-White race, and less likely to have human immunodeficiency virus infection, or cavitary pulmonary disease. During 2014-2017, non-US-born persons with TB were more likely to have diabetes mellitus, while the US-born were more likely to have smear-positive TB and use non-injecting drugs.CONCLUSION: Changes in epidemiologic trends are likely to affect TB incidence in the coming decades. The Centers for Disease Control and Prevention has called for increased attention to TB prevention through the detection and treatment of latent tuberculous infection.

Estimating tuberculosis cases and their economic costs averted in the United States over the past two decades

BACKGROUND

Following a concerted public health response to the resurgence of tuberculosis (TB) in the United States in the late 1980s, annual TB incidence decreased substantially. However, no estimates exist of the number and cost savings of TB cases averted.

METHODS

TB cases averted in the United States during 1995-2014 were estimated: Scenario 1 used a static 1992 case rate; Scenario 2 applied the 1992 rate to foreign-born cases, and a pre-resurgence 5.1% annual decline to US-born cases; and a statistical model assessed human immunodeficiency virus and TB program indices. We applied the cost of illness to estimate the societal benefits (costs averted) in 2014 dollars.

RESULTS

During 1992-2014, 368 184 incident TB cases were reported, and cases decreased by two thirds during that period. In the scenarios and statistical model, TB cases averted during 1995-2014 ranged from approximately 145 000 to 319 000. The societal benefits of averted TB cases ranged from US$3.1 to US$6.7 billion, excluding deaths, and from US$6.7 to US$14.5 billion, including deaths.

CONCLUSIONS

Coordinated efforts in TB control and prevention in the United States yielded a remarkable number of TB cases averted and societal economic benefits. We illustrate the value of concerted action and targeted public health funding.

Prospective study of etiologic agents of community-acquired pneumonia in patients with HIV infection

OBJECTIVES

To study prospectively HIV-positive patients admitted to the hospital because of pneumonia by extensive laboratory tests to determine specific microbiologic diagnoses and to establish the best clinical diagnosis after review of all available data by expert clinicians.

METHODS

Patients admitted to one of two hospitals had extensive questionnaires completed and defined diagnostic tests performed on blood, sputum, urine and bronchoalveolar lavage specimens, when available.

RESULTS

A total of 230 patients had a diagnosis of pneumonia verified. A definite or probable etiologic diagnosis was made in 155 (67%) of these patients. Pneumocystis carinii caused 35% of all cases of pneumonia. Twenty-seven percent of cases of pneumonia with a single etiology had a definite or probable bacterial etiology. 'Atypical agents' were distinctly uncommon. Few clinical or laboratory parameters could differentiate specific etiologies.

CONCLUSIONS

P. carinii continues to be a common cause of pneumonia in these patients. The rarity of 'atypical agents' could simplify the empiric approach to therapy. Despite the use of extensive testing we did not find a definite etiology in a large number of cases.

Survey of obstetrician-gynecologists in the United States about toxoplasmosis

Background: Although the incidence of toxoplasmosis is low in the United States, up to 6000 congenital cases occur annually. In September 1998, the Centers for Disease Control and Prevention held a conference about toxoplasmosis; participants recommended a survey of the toxoplasmosis-related knowledge and practices of obstetrician-gynecologists and the development of professional educational materials for them.

Methods: In the fall of 1999, surveys were mailed to a 2% random sample of American College of Obstetricians and Gynecologists (ACOG) members and to a demographically representative group of ACOGmembers known as the Collaborative Ambulatory Research Network (CARN). Responses were not significantly different for the random and CARN groups for most questions (p value shown when different).

Results: Among 768 US practicing ACOG members surveyed, 364 (47%) responded. Seven per cent (CARN 10%, random 5%) had diagnosed one or more case(s) of acute toxoplasmosis in the past year. Respondents were well-informed about how to prevent toxoplasmosis. However, only 12% (CARN 11%, random 12%) indicated that a positive Toxoplasma IgM test might be a false–positive result, and only 11% (CARN 14%, random 9%) were aware that the Food and Drug Administration sent an advisory to all ACOG members in 1997 stating that some Toxoplasma IgM test kits have high false–positive rates. Most of those surveyed (CARN 70%, random 59%; X²p < 0.05) were opposed to universal screening of pregnant women.

Conclusions: Many US obstetrician-gynecologists will encounter acute toxoplasmosis during their careers, but they are frequently uncertain about interpretation of the laboratory tests for the disease. Most would not recommend universal screening of pregnant women.

Effect of mutations in Pneumocystis carinii dihydropteroate synthase gene on outcome of P carinii pneumonia in patients with HIV-1: a prospective study

BACKGROUND

Investigators have reported that patients infected with Pneumocystis carinii containing mutations in the DHPS (dihydropteroate synthase) gene have a worse outcome than those infected with P carinii containing wild-type DHPS. We investigated patients with HIV-1 infection and P carinii pneumonia to determine if DHPS mutations were associated with poor outcomes in these patients.

METHODS

We compared presence of mutations at the DHPS locus with survival and response of patients to co-trimoxazole or other drugs.

FINDINGS

For patients initially given co-trimoxazole, nine (14%) of 66 with DHPS mutant died, compared with nine (25%) of 36 with wild type (risk ratio50.55 [95% CI=0.24-1.25]; p=0.15). Ten (15%) of 66 patients with a DHPS mutant did not respond to treatment, compared with 13 (36%) of 36 patients with the wild type (0.42 [0.20-0.86]; p=0.02). For patients aged 40 years or older, four (14%) of 29 with the mutant and nine (56%) of 16 with the wild type died (0.25 [0.09-0.67]; p=0.005).

INTERPRETATION

These results, by contrast with those of previous studies, suggest that patients with wild-type P carinii do not have a better outcome than patients with the mutant when given co-trimoxazole. Our results suggest that presence of a DHPS mutation should be only one of several criteria guiding the choice of initial drug treatment of P carinii pneumonia in patients with HIV-1 infection.

Survival of patients with AIDS, after diagnosis of Pneumocystis carinii pneumonia, in the United States

To examine survival after diagnosis of Pneumocystis carinii pneumonia (PCP) and factors associated with early death (during the month of or the month after diagnosis of PCP), data were analyzed from the Adult and Adolescent Spectrum HIV Disease project. Among 4412 patients with 5222 episodes of PCP during follow-up (1992-1998), survival at >1 month after diagnosis was 82%, and survival at > or =12 months after diagnosis was 47%; 12-month survival increased from 40% in 1992-1993 to 63% in 1996-1998. By multiple logistic regression analysis, early death was associated with history of PCP (odds ratio [OR], 1.4), age 45-59 years (OR, 1.9) or > or =60 years (OR, 3.7), and CD4 cell count of 0-24 cells/microL (< or =5 months before PCP; OR, 1.8) or 25-49 cells/microL (OR, 1.4) (P<.05). Concurrent prescription of combination antiretroviral therapy (OR, 0.2) and other antiretroviral therapy (OR, 0.4) was associated with surviving the early period. This study shows improved survival after diagnosis of PCP in recent years, despite emergence of antibiotic-resistant mutant P. carinii strains.

Cutaneous leishmaniasis in Guatemala: people's knowledge, concepts and practices

Ten rural communities in the northern area of Guatemala where cutaneous leishmaniasis (CL) is endemic were investigated to determine the residents' knowledge of the disease, their related concepts and practices, and their treatment preferences, and to identify the communication channels they use to acquire information. Of 425 heads of household interviewed, 96.7% could accurately describe a typical CL lesion. CL was found to be the fourth most frequently mentioned disease (in studies based on a free list format) and to be considered the sixth most serious (in studies based on paired comparisons). A series of three-way comparisons, used to analyse the subjects' concepts about the similarities of various discases, indicated that CL was considered to be most closely related to skin problems and to be different from any other group of diseases. All interviewees believed that it was necessary to receive treatment for CL, because without treatment the disease would progress, reach the bone, and take years to heal. More than half (55%) of the respondents knew about meglumine antimonate (Glucantime), the most commonly prescribed drug for treating CL in Guatemala. Only a few communication channels that were used by respondents to receive information were identified; the use of radio broadcasts and direct communication via the community leaders appeared to be the most effective.

Sulfa or sulfone prophylaxis and geographic region predict mutations in the Pneumocystis carinii dihydropteroate synthase gene

To determine factors associated with mutations in the Pneumocystis carinii dihydropteroate synthase (DHPS) gene, a prospective study of human immunodeficiency virus (HIV)-infected patients with confirmed P. carinii pneumonia was conducted in Atlanta, Seattle, and San Francisco. Clinical information was obtained from patient interview and chart abstraction. DHPS genotype was determined from DNA sequencing. Overall, 76 (68.5%) of 111 patients had a mutant DHPS genotype, including 22 (81.5%) of 27 patients from San Francisco. In multivariate analysis, sulfa or sulfone prophylaxis and study site were independent predictors of a mutant genotype. Fourteen (53.8%) of 26 patients who were newly diagnosed with HIV infection and had never taken prophylaxis had a mutant genotype. The significance of geographic location as a risk factor for mutant genotype and the high proportion of mutant genotypes among persons never prescribed prophylaxis, including those newly diagnosed with HIV infection, provide indirect evidence that these mutations are transmitted from person to person either directly or through a common environmental source.

Preventing congenital toxoplasmosis

SCOPE OF THE PROBLEM

Toxoplasmosis is caused by infection with the protozoan parasite Toxoplasma gondii. Acute infections in pregnant women can be transmitted to the fetus and cause severe illness (e.g., mental retardation, blindness, and epilepsy). An estimated 400-4,000 cases of congenital toxoplasmosis occur each year in the United States. Of the 750 deaths attributed to toxoplasmosis each year, 375 (50%) are believed to be caused by eating contaminated meat, making toxoplasmosis the third leading cause of foodborne deaths in this country.

ETIOLOGIC FACTORS

Toxoplasma can be transmitted to humans by three principal routes: a) ingestion of raw or inadequately cooked infected meat; b) ingestion of oocysts, an environmentally resistant form of the organism that cats pass in their feces, with exposure of humans occurring through exposure to cat litter or soil (e.g., from gardening or unwashed fruits or vegetables); and c) a newly infected pregnant woman passing the infection to her unborn fetus. RECOMMENDATIONSFOR PREVENTION: Toxoplasma infection can be prevented in large part by a) cooking meat to a safe temperature (i.e., one sufficient to kill Toxoplasma); b) peeling or thoroughly washing fruits and vegetables before eating; c) cleaning cooking surfaces and utensils afterthey have contacted raw meat, poultry, seafood, or unwashed fruits or vegetables; d) pregnant women avoiding changing cat litter or, if no one else is available to change the cat litter, using gloves, then washing hands thoroughly; and e) not feeding raw or undercooked meat to cats and keeping cats inside to prevent acquisition of Toxoplasma by eating infected prey.

RESEARCH AGENDA

Priorities for research were discussed at a national workshop sponsored by CDC in September 1998 and include a) improving estimates of the burden of toxoplasmosis, b) improving diagnostic tests to determine when a person becomes infected with Toxoplasma, and c) determining the applicability of national screening programs.

CONCLUSION

Many cases of congenital toxoplasmosis can be prevented. Specific measures can be taken by women and their health-care providers to decrease the risk for infection during pregnancy and prevent severe illness in newborn infants.

Genetic variation in Pneumocystis carinii isolates from different geographic regions: implications for transmission

To study transmission patterns of Pneumocystis carinii pneumonia (PCP) in persons with AIDS, we evaluated P. carinii isolates from patients in five U.S. cities for variation at two independent genetic loci, the mitochondrial large subunit rRNA and dihydropteroate synthase. Fourteen unique multilocus genotypes were observed in 191 isolates that were examined at both loci. Mixed infections, accounting for 17.8% of cases, were associated with primary PCP. Genotype frequency distribution patterns varied by patients' place of diagnosis but not by place of birth. Genetic variation at the two loci suggests three probable characteristics of transmission: that most cases of PCP do not result from infections acquired early in life, that infections are actively acquired from a relatively common source (humans or the environment), and that humans, while not necessarily involved in direct infection of other humans, are nevertheless important in the transmission cycle of P. carinii f. sp. hominis.

Risk factors for community-acquired pneumonia among persons infected with human immunodeficiency virus

Two hundred eleven adults with human immunodeficiency virus (HIV) infection hospitalized for community-acquired pneumonia, including Pneumocystis carinii pneumonia (PCP; patients), and 192 matched HIV-infected hospitalized patients without pneumonia (controls) were interviewed to determine risk factors for pneumonia. Multivariate logistic regression showed that patients were less likely than controls to have used trimethoprim-sulfamethoxazole (TMP-SMZ) prophylaxis (odds ratio [OR], 0.22; 95% confidence interval [CI], 0.12-0.41) and more likely to have been hospitalized previously with pneumonia (OR, 6.25; CI, 3.40-11.5). Patients were also more likely than controls to have gardened (OR, 2.24; CI, 1.00-5.02) and to have camped or hiked (OR, 4.95; CI, 1.31-18.7), but stratified analysis by etiologic agent showed this association only for PCP. These findings reconfirm the efficacy of TMP-SMZ in preventing community-acquired pneumonia. In addition, hospitalization for pneumonia might represent a missed opportunity to encourage HIV-infected patients to enter into regular medical care and to adhere to prescribed antiretroviral and prophylaxis medications.

Declining CD4+ T-lymphocyte counts are associated with increased risk of enteric parasitosis and chronic diarrhea: results of a 3-year longitudinal study

From January 1991 through September 1994, we observed people who were infected with HIV to assess the impact of enteric parasite-associated diarrhea. Respondents answered comprehensive questionnaires covering clinical and epidemiologic information and provided stool specimens monthly, which were examined unstained as well as stained with trichrome, chromotrope 2R, and with Kinyoun carbol-fuchsin, and with indirect immunofluorescence for Cryptosporidium. In all, 602 participants, who were interviewed, provided stool specimens at 3254 monthly visits. Parasites were associated with 50 of 354 (14.1%) acute diarrheal episodes (lasting < or = 28 days) and with 97 of 279 (34.8%) chronic episodes (lasting > 28 days). A parasite was associated with 31 of 222 (14.0%) episodes that occurred when CD4+ counts were > or = 200 cells/microl and with 150 of 566 (26.5%) episodes that occurred when CD4+ counts were < 200 cells/microl. The most commonly identified parasite was C. parvum, which was associated with 18 of 354 (5.1%) acute episodes and 36 (12.9%) of the 279 chronic episodes of diarrhea. In this patient population, enteric protozoan parasites were commonly associated with illness, particularly as immunosuppression worsened, and were more likely to be associated with chronic rather than acute diarrhea.

Risk factors for primary Pneumocystis carinii pneumonia in human immunodeficiency virus-infected adolescents and adults in the United States: reassessment of indications for chemoprophylaxis

Risk factors for the development of a first episode of Pneumocystis carinii pneumonia (PCP) were investigated in the Adult and Adolescent Spectrum of Disease Project, a medical record review study involving longitudinal follow-up of human immunodeficiency virus-infected adults in 9 US cities. Risk factors included decreasing CD4 lymphocyte count and history of AIDS-defining illness, non-P. carinii pneumonia, oral thrush, or unexplained fever for > or = 2 days; PCP prophylaxis was protective. PCP incidence/100 person-years of observation among persons not prescribed PCP prophylaxis was higher in those with CD4 lymphocyte counts < 250 cells/microL or CD4 cell percent < 14% (8.3; 95% confidence interval [CI], 7.7-9.0) than in persons with CD4 cell counts < 200 or history of thrush or fever, which constitute current criteria for prophylaxis against PCP (5.9; 95% CI, 5.5-6.4). Because of increased efficiency in capturing persons at highest risk, CD4 cell count < 250 or CD4 cell percent < 14% should be considered as criteria for prophylaxis against first episodes of PCP.

Possible effectiveness of clarithromycin and rifabutin for cryptosporidiosis chemoprophylaxis in HIV disease. HIV Outpatient Study (HOPS) Investigators

CONTEXT

Cryptosporidium parvum infection, a common cause of diarrhea in persons infected with the human immunodeficiency virus (HIV), is difficult to treat or prevent.

OBJECTIVE

To evaluate relative rates of cryptosporidiosis in HIV-infected patients who were either receiving or not receiving chemoprophylaxis or treatment for Mycobacterium avium complex.

DESIGN

Analysis of prospectively collected data from HIV-infected patients' visits to their physicians since 1992.

SETTING

Ten (8 private, 2 publicly funded) HIV clinics in 9 US cities.

PATIENTS

A total of 1019 HIV-infected patients with CD4+ cell counts less than 0.075 x 10(9)/L.

MAIN OUTCOME MEASURES

Incidence of clinical cryptosporidiosis during treatment with clarithromycin, rifabutin, and azithromycin.

RESULTS

Five of the 312 patients reportedly taking clarithromycin developed cryptosporidiosis vs 30 of the 707 patients not taking clarithromycin (relative hazard [RH], 0.25 [95% confidence interval (CI), 0.10-0.67]; P=.004). Two of the 214 patients taking rifabutin developed cryptosporidiosis vs 33 of the 805 not taking rifabutin (RH, 0.15 [95% CI, 0.04-0.62]; P=.01). Prophylactic efficacy of either drug was 75% or greater. No protective effect was seen in the 54 patients reportedly taking azithromycin (RH, 1.48 [95% CI, 0.44-5.04]; P=.46).

CONCLUSIONS

Clarithromycin and rifabutin were highly protective against development of cryptosporidiosis in immune-suppressed HIV-infected persons in this analysis; further study is warranted.

Toxoplasmic encephalitis in HIV-infected persons: risk factors and trends. The Adult/Adolescent Spectrum of Disease Group

OBJECTIVE

To evaluate the incidence of and risk factors for toxoplasmic encephalitis among HIV-infected persons.

DESIGN

Medical facility-based prospective medical record reviews of consecutive patients.

METHODS

We analysed data collected from January 1990 through August 1995 in more than 90 inpatient and outpatient medical facilities in nine US cities. Incidence was calculated as cases per 100 person-years and risk ratios (RR) for annual incidence were calculated using proportional hazards regression while controlling for city, sex, race, age, county of birth, HIV exposure mode, and prior prescription of trimethoprim-sulfamethoxazole (TMP-SMX).

RESULTS

The incidence of TE was 4.0 cases per 100 person-years among persons with a CD4+ T-lymphocyte count of < 100 x 10(6)/l. In multivariate analysis, among the nine cities the annual incidence of toxoplasmosis was significantly lower only in Denver [RR, 0.3; 95% confidence interval (CI), 0.1-0.7; referent city, Seattle]. Persons prescribed TMP-SMX were half as likely to develop toxoplasmic encephalitis as those who were not (RR, 0.5; 95% CI, 0.4-0.7). Of the 4173 persons with AIDS (1987 Centers for Disease Control and Prevention definition) who died during the study period, 267 (6.4%) had toxoplasmic encephalitis in the course of HIV disease.

CONCLUSIONS

Toxoplasmic encephalitis in HIV-infected persons varies by geographic area in the United States. TMP-SMX reduces the risk for toxoplasmic encephalitis.

Preventing Pneumocystis carinii pneumonia in persons infected with human immunodeficiency virus

Although the incidence of Pneumocystis carinii pneumonia (PCP) among adults infected with human immunodeficiency virus (HIV) has declined, no decline in PCP incidence has been observed among HIV-infected children, and PCP remains the most common serious opportunistic infection among both adults and children in the United States. Some evidence of airborne transmission of P. carinii exists, and some clusters of cases of PCP have been reported; however, data are insufficient to recommend that persons with PCP be separated from immunosuppressed persons as a standard practice. The incidence of PCP can be reduced substantially if persons at risk for PCP are identified and receive adequate chemoprophylaxis. Several drugs and drug combinations are highly effective in preventing PCP. For both adults and children, oral trimethoprim-sulfamethoxazole (TMP-SMZ) is the preferred form of prophylaxis. Adverse effects are commonly associated with the use of TMP-SMZ and in some cases may necessitate withdrawal of the drug until the effects resolve. However, reintroduction at the same dose or at a lower and gradually increasing dose will often permit the continued use of TMP-SMZ. For persons intolerant of TMP-SMZ, dapsone alone and dapsone plus pyrimethamine are effective alternatives. A third alternative is aerosolized pentamidine. Additional drugs of unproven efficacy but of potential use in exceptional cases are available.

Efficacy of a short course (10 days) of high-dose meglumine antimonate with or without interferon-gamma in treating cutaneous leishmaniasis in Guatemala

Sixty-six Guatemalan men with parasitologically confirmed cutaneous leishmaniasis, due most commonly to Leishmania braziliensis, were randomly assigned to receive one of three treatment regimens: meglumine antimonate (meglumine) for 20 days; meglumine for 10 days; and meglumine for 10 days plus alternate-day injections of interferon-gamma. In each group, meglumine was given intravenously as 20 mg of antimony/(kg of body weight.d). All treatment regimens were associated with similar response rates: the lesions of 19 (90%) of 21 patients who received meglumine for 20 days, 18 (90%) of 20 patients who received meglumine for 10 days, and all 22 patients who received meglumine plus interferon-gamma were completely reepithelialized by 13 weeks. In addition, for patients receiving all treatment regimens, test-of-cure cultures for Leishmania were negative and reactivation of lesions did not occur during 12 months of follow-up. The high efficacy of our 10-day course of meglumine indicates that the currently recommended duration of 20 days may be unnecessary for infections caused by L. braziliensis and suggests that a 10-day course of high-dose antimony should be tested as therapy for cutaneous leishmaniasis in other geographic areas.

Isolation of Leishmania braziliensis from Lutzomyia ovallesi (Diptera:Psychodidae) in Guatemala

Leishmania braziliensis is endemic in Guatemala and Belize in Central America. To help identify the vector(s) of this parasite in Guatemala, phlebotomine sand flies that were aspirated from the clothing of collectors at Tikal National Park in the Department of the Peten were examined for flagellates. Lutzomyia ovallesi was found infected with flagellates that were identified as L. braziliensis by isoenzyme electrophoresis. The isoenzyme profile of this isolate matched those from humans from the same area.

The natural history of cutaneous leishmaniasis in Guatemala

The natural history of American cutaneous leishmaniasis was studied in Guatemala by analyzing the characteristics of 355 untreated leishmanial lesions, observing the evolution of 57 lesions on persons who received a placebo in treatment trials, and analyzing data from a population-based survey concerning the duration of 82 untreated lesions. Of 25 lesions caused by Leishmania mexicana that were followed prospectively, 22 (88%) completely reepithelialized by a median lesion age of 14 weeks, and 17 (68%) were classified as cured (no residual wound inflammation or reactivation during at least 6 months of follow-up). In contrast, 7 (22%) of 32 lesions caused by Leishmania braziliensis reepithelialized by a median lesion age of 13 weeks, and only 2 (6%) cured. These data demonstrate that the species of Leishmania is the primary determinant of the clinical course and outcome of untreated lesions and underscore the need for field-applicable diagnostic techniques that provide rapid species identification.

Placebo-controlled clinical trial of sodium stibogluconate (Pentostam) versus ketoconazole for treating cutaneous leishmaniasis in Guatemala

To determine the relative efficacy and toxicity of stibogluconate and ketoconazole for the treatment of cutaneous leishmaniasis, a comparative trial was conducted in which 120 Guatemalan men with parasitologically proven cutaneous leishmaniasis were randomly divided into three treatment groups: sodium stibogluconate (20 mg of antimony per kilogram per day intravenously for 20 days), ketoconazole (600 mg per day orally for 28 days), and placebo. Treatment outcome was influenced by species. Among patients infected with Leishmania braziliensis, 24 (96%) of 25 in the stibogluconate group but only 7 (30%) of 23 in the ketoconazole group responded. Among Leishmania mexicana-infected patients, only 4 (57%) of 7 in the stibogluconate group but 8 (89%) of 9 in the ketoconazole group responded. These differences emphasize the importance of speciation in the treatment of leishmaniasis.

Comparison of active and passive case detection of cutaneous leishmaniasis in Guatemala

To estimate the degree to which passive case detection underestimates the true incidence of cutaneous leishmaniasis in Guatemala, we compared data from the passive surveillance system of the Guatemalan Ministry of Health with a cross-sectional population-based survey of cutaneous leishmaniasis in Guatemala. Of the 2,938 persons interviewed, 143 (5%) reported having had cutaneous leishmaniasis at some time in the past, 37 (1.3%) reported the onset of infection in the 12 months before the survey, 31 (1.1%) had active infections, and 16 (0.5%) had parasitologically confirmed infections. Calculated on the basis of these reports and the estimated population of the endemic area, the total number of new cases in the leishmaniasis-endemic area in the 12 months before the survey was approximately 2,574; during the same 12 month period, Ministry of Health data based on passive surveillance listed 64 cases of cutaneous leishmaniasis. In Guatemala, incidence estimates based on passive surveillance may underestimate the occurrence of cutaneous leishmaniasis by as much as a factor of 40.

Placebo-controlled clinical trial of meglumine antimonate (glucantime) vs. localized controlled heat in the treatment of cutaneous leishmaniasis in Guatemala

Sixty-six Guatemalans with parasitologically proven cutaneous leishmaniasis were randomly and equally divided into 3 treatment groups: those receiving meglumine antimonate (Glucantime), 850 mg antimony/day im for 15 days; those receiving localized controlled heat from a radio-frequency generator, 50 degrees C for 30 sec, 3 treatments at 7 day intervals; and those receiving treatment with a placebo. Of 53 isolates identified, 40 were Leishmania braziliensis braziliensis and 13 were L. mexicana mexicana. Thirteen weeks after beginning treatment, the number of patients from each group with completely healed and parasitologically negative lesions were as follows: meglumine antimonate, 16 (73%); localized heat, 16 (73%); and placebo, 6 (27%). The cure rate for those with infections due to L. b. braziliensis in each group was as follows: meglumine antimonate, 11 out of 14 (79%); controlled heat, 9 out of 14 (64%); and placebo, 0 out of 11.

Cutaneous leishmaniasis in Guatemala: comparison of diagnostic methods

A comparison was made of methods used to diagnose suspected cutaneous leishmaniasis in Guatemala. The most sensitive method was a combination of thin smears made from superficial scrapings of the ulcers and inoculation of culture medium with either aspirates or scrapings. The diagnosis was confirmed in 252 (70%) of 362 patients. Ability to cultivate Leishmania was correlated with the concentration of amastigotes seen on thin smears. Leishmania were cultured in 42 (27%) of 153 patients with no amastigotes found in 400 oil-immersion fields and in 174 (83%) of 209 patients with at least 1 amastigote. No difference in diagnostic outcome was found when we compared smears or cultures taken from the center or the border of the ulcer or from an incision made tangential from the ulcer. We found no difference when we compared smears obtained with scalpels, capillary tubes, or dental broaches. The use of scrub brushes soaked in iodine neither decreased the rate of culturing parasites nor decreased contamination rates.

Effect of immunoglobulin M from normal human serum on Leishmania donovani promastigote agglutination, complement-mediated killing, and phagocytosis by human monocytes

Serum from healthy, nonimmune humans contained immunoglobulin M (IgM) antibodies that agglutinated Leishmania donovani promastigotes, activated complement, and enhanced promastigote ingestion by human monocytes. The findings indicate that IgM antibodies have the capacity to affect the initial interaction of L. donovani promastigotes with human host defenses.

Cutaneous leishmaniasis in Guatemala: isoenzyme characterization of isolates from humans

Leishmania organisms cultivated from cutaneous lesions of humans in Guatemala were characterized by cellulose acetate electrophoresis. Six isolates had electrophoretic enzyme patterns identical to World Health Organization reference strains of Leishmania braziliensis braziliensis, and 5 had patterns identical to reference strains of Leishmania mexicana mexicana.

Effect of azotemia in dogs on the pharmacokinetics of pentamidine

We used a new high-performance liquid-chromatography assay to study the pharmacokinetics of pentamidine isethionate given intravenously to 10 dogs before and after surgically induced renal failure. The presurgery peak serum concentration of pentamidine averaged 867 ng/ml and by 6 hr had fallen to 30 ng/ml. After surgery the peak and 6-hr concentrations were 780 ng/ml and 28 ng/ml. Mean total body clearance of pentamidine before surgery was 46.7 ml/min per kg, of which only 2.0 ml/min per kg was due to renal clearance had fallen 80%--to 0.4 ml/min per kg. Two dogs with azotemia and two control dogs received 14 daily infusions of pentamidine. Kinetic parameters measured after the last dose were not significantly different from those after the first dose, and the amount of pentamidine recovered from tissues was similar for dogs with azotemia and controls. In summary, because renal clearance of pentamidine accounted for such a small proportion of total body clearance, none of the parameters measured was affected significantly by moderate azotemia.

Outbreak of parasitic gastroenteritis among travelers returning from Africa

Eosinophilia and intestinal infections with a trematode parasite developed in 18 of the 20 American tourists who traveled to Kenya and Tanzania; the fact that the two other tourists also had eosinophilia suggested that they too had been infested. Because no adult flukes were recovered, a specific identification could not be made, but the eggs we observed resembled those of an Echinostoma. Several tour members had mild, nonspecific abdominal complaints, but ten had moderately severe abdominal cramps and loose or watery stools. Treatment with praziquantel was associated with rapid symptomatic improvement, and after treatment no parasitic eggs were recovered from patients' stools.

High-performance liquid chromatographic method for quantitation of pentamidine in blood serum

A high-performance liquid chromatographic procedure has been developed for the determination of pentamidine concentrations in serum samples. A microbore, reversed-phase column was used with a mobile phase consisting of methanol and water with sodium heptanesulfonate and triethylamine as modifiers. Pentamidine could be extracted from serum only by the addition of an ion-pairing agent, di(2-ethylhexyl) phosphoric acid, to the chloroform used for extraction. The method can be used to reliably detect levels as low as 5 ng/ml. The pentamidine concentration in the serum of eleven patients 24 h after their tenth daily dose of pentamidine averaged 60 +/- 34 ng/ml.

Epidemiologic study of visceral leishmaniasis in Honduras, 1975-1983

Between 1975 and 1983, 53 patients with parasitologically proven visceral leishmaniasis (VL) and 16 patients with suspected VL were diagnosed in Honduras. The patients' ages ranged from 3 months to 10 years, but 95% were younger than 3 years old. Since 1978, when 16 patients were reported, the yearly incidence has declined, and in 1982 only 4 patients were reported. We located and interviewed the families of 57 of the 69 patients. At the onset of illness, all 57 patients lived in rural areas, and 55 lived in southern Honduras. All the patients who were discharged from the hospital alive were still living at the time of the interview. A case-control study, using age-matched neighbors as controls, showed that patients were significantly more likely to have lived in poorly constructed, wood-stick houses. We used an indirect immunofluorescence test to analyze blood samples for Leishmania antibodies from 218 family members of patients, 170 family members of controls, and 156 children living on the island of El Tigre, where 4 of the 5 most recently diagnosed patients lived. Although 15 specimens gave a positive reaction to L. donovani antigen, each gave a stronger reaction when tested against Trypanosoma cruzi antigen, suggesting that the reactions to L. donovani were false positives. A serosurvey of 279 dogs of cases and controls and from El Tigre showed that 24 had positive reactions to L. donovani antigen, but only 4 (1.4%) had higher titers to L. donovani than to T. cruzi.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-control study of waterborne giardiasis in Reno, Nevada

An outbreak of Giardia lamblia gastroenteritis occurred in Reno, Nevada, in 1982, during which 324 laboratory-confirmed infections were reported. During the outbreak, Reno was supplied in part by surface water that was chemically coagulated, settled, and chlorinated, but was not filtered. Giardia cysts were recovered from the water supply, and a beaver infected with Giardia was found in one of the reservoirs. A case-control study indicated that, during the outbreak but not afterwards, persons with giardiasis drank more municipal water than did controls. Corrective measures, which included removing the infected beaver and increasing the chlorine concentration, were followed by a rapid decrease in reports of giardiasis.

Cryptosporidiosis in humans: review of recent epidemiologic studies

Since 1976, when Cryptosporidium was first recognized as a human pathogen, understanding of the epidemiology of this protozoan parasite has increased substantially. This review discusses 14 recently published studies of the occurrence of cryptosporidiosis in developed and developing countries and compares their findings with those of previous epidemiologic reports. These studies show that cryptosporidiosis is an important public health problem worldwide. Although cryptosporidiosis was first recognized as a problem in immunosuppressed patients, persons with normal immunologic function are also affected. This appears to be especially true for children in developing countries; of 1035 children with diarrhea reported in several surveys, 79 (7.6%) had Cryptosporidium. Findings from studies that included both asymptomatic as well as symptomatic persons have demonstrated that Cryptosporidium infections are rare in persons without symptoms, suggesting that Cryptosporidium should not be thought of as an opportunistic parasite. Early studies documented the potential for animal-to-human transmission of Cryptosporidium, but it is now clear that many, perhaps most, Cryptosporidium infections in humans are not acquired directly from infected animals. Although alternate modes of transmission are just beginning to be explored, evidence indicates that person-to-person spread is important.

Human and sylvatic Trypanosoma cruzi infection in California

In August 1982, a 56-year-old woman from Lake Don Pedro, California, developed acute Chagas' disease (American trypanosomiasis). She had not traveled to areas outside the United States with endemic Chagas' disease, she had never received blood transfusions, and she did not use intravenous drugs. Trypanosoma cruzi cultured from the patient's blood had isoenzyme patterns and growth characteristics similar to T. cruzi belonging to zymodeme Z1. Triatoma protracta (a vector of Trypanosoma cruzi) infected with T. cruzi were found near the patient's home, a trypanosome resembling T. cruzi was cultured from the blood of two of 19 ground squirrels (Spermophilus beecheyi), and six of 10 dogs had antibody to T. cruzi. A serosurvey of three groups of California residents revealed antibody to T. cruzi by complement fixation in six of 237 (2.5 per cent) individuals living near the patient and in 12 of 1,706 (0.7 per cent) individuals living in a community 20 miles northeast of the patient's home, but in only one of 637 (0.2 per cent) blood donors from the San Francisco Bay area. This is the first case of indigenously acquired Chagas' disease reported from California and the first case recognized in the United States since 1955. This investigation suggests that transmission of sylvatic Trypanosoma cruzi infection to humans occurs in California but that Chagas' disease in humans is rare.

Cryptosporidiosis: clinical, epidemiologic, and parasitologic review

Cryptosporidium, an intestinal protozoan parasite, is a well-known cause of diarrhea in animals but has been recognized only recently as a cause of human disease. Since 1976, 58 cases of cryptosporidiosis in humans have been reported; 18 of the patients had normal immune function, and 40 had various immunologic abnormalities, the most common of which, acquired immune deficiency syndrome (AIDS), occurred in 33 patients. Patients with normal immune function had self-limited diarrhea, but patients with immunologic abnormalities often developed severe, irreversible diarrhea; 22 patients have died. The diagnosis of cryptosporidiosis can now be made noninvasively, but increased diagnostic proficiency has led to little improvement in control or treatment of the disease. Although 23 compounds have been evaluated in experimentally infected animals and 20 drugs have been used in human clinical trials, no effective chemotherapeutic agent for cryptosporidiosis has been identified to date.