Cluster of HIV-Positive Young Women—New York, 1997-1998 FREE

MMWR. 1999;48:413-416

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As of July 1997, six human immunodeficiency virus (HIV) infections in young women who reported sexual contact with the same HIV-infected man (putative index case-patient) were detected at health-service clinics in a rural county in upstate New York. During the next several months, other sexual contacts of the man were discovered by public health officials through routine voluntary partner notification interviews, interviews with exposed women, and after a public announcement resulted in counseling and testing of approximately 1400 persons in the county. This report presents epidemiologic and laboratory findings of the young women investigated as part of this cluster and suggests a common source of HIV infection for these women.*

For this investigation, female sex partners of the putative index case-patient were considered primary contacts, male sex partners of HIV-infected primary contacts were considered secondary contacts, and female sex partners of the HIV-infected male secondary contacts were considered tertiary contacts. Medical records of contacts were reviewed for demographic information, history of HIV counseling and testing, sexually transmitted diseases (STDs) (i.e., syphilis, gonorrhea, chlamydia, herpes, and trichomonas), and drug and alcohol use. Blood specimens from consenting persons were forwarded to CDC for HIV DNA sequence analysis and for blinded serologic testing of specimens for syphilis, Chlamydia trachomatis, and herpes simplex virus type 2 (HSV-2). No blood specimen was available from the putative index case-patient.

Forty-seven primary contacts were identified and reportedly had had vaginal sex with the index patient: 13 (31%) of 42 tested had HIV infection. From these 13 primary contacts, 84 secondary contacts were identified; one of 50 tested had HIV infection. Sixty secondary contacts had sexual exposure to the primary contacts during the same period or after the primary contacts had sexual exposure to the putative index case-patient; one of 39 tested had HIV infection. Three tertiary contacts of the one positive secondary contact were identified; the one tested was HIV negative. One of three infants born to HIV-infected women was positive by polymerase chain reaction (PCR) testing for HIV DNA. There was no evidence that the putative index case-patient or the HIV-infected primary contacts had had same-sex or needle-sharing contacts.

Blood samples for HIV DNA sequence analysis were obtained from 10 of the 13 HIV-infected primary contacts, the one HIV-infected secondary contact, and two HIV-infected persons from the community who were not epidemiologically related to the cluster (community-comparison persons). A nested PCR procedure was used to amplify proviral HIV DNA sequences from peripheral blood mononuclear cells (PBMCs) from these 13 persons. A 345 nucleotide segment of the C2V3C3 region of the env gene and approximately 400 nucleotides of the p17 coding region of gag were sequenced and analyzed in a blinded fashion. Phylogenetic analysis of the 13 sequences was performed with reference sequences from HIV subtypes A-D, F, and G from the GenBank† database for both the env and gag gene regions. Bootstrapping, a technique used to assess the relatedness of the viruses, demonstrated that all 13 sequences were from subtype B viruses.¹ Sequences from the 10 HIV-infected primary contacts—but not from the infected secondary contact, the two community-comparison persons, or subtype B reference strains—clustered strongly together in both gene regions. The phylogenetic analyses indicated a high degree of relatedness among the viruses infecting the 10 tested primary contacts and suggest that the infected secondary contact was probably infected by a source not related to this cluster.

The 13 HIV-infected primary contacts reportedly had their last sexual exposure to the putative index case-patient during February 1996-January 1997; 25 of the 29 primary contacts who were not HIV infected had last contact with him during January 1995-August 1997; data were missing for four. The median number of vaginal sexual exposures to the putative index case-patient was higher, although not significantly, for the HIV-infected women (six exposures; range: two-190 exposures) than for the uninfected women (three exposures; range: one-90 exposures) (data were missing for six) (Wilcoxon rank sum test, p=0.07). Median ages at first exposure to the putative index case-patient were similar for HIV-infected women (17.8 years; range: 13-22 years) (data were missing for one) and uninfected women (17.7 years; range: 14-24 years) (data were missing for 14). Among exposed women, HIV infection was not associated significantly with a history of STDs (10 of 22), cocaine use (three of 22), alcohol use (two of 16), or serologic markers for STDs (15 of 25). When analyses were limited to seven HIV-infected and eight uninfected women with exposures only after September 1996, HIV-infected women had significantly more exposures to the putative index case-patient (median: three exposures; range: two-six exposures) than the uninfected women (median: one exposure; range: one-two exposures (data were missing for two) (Wilcoxon rank sum test, p=0.005).

FB Coles, DO, GS Birkhead, MD, P Johnson, PF Smith, MD, State Epidemiologist, New York State Dept of Health; R Berke, MD, P Allenson, M Clark, Chautauqua County Dept of Health, Mayville, New York. Div of HIV/AIDS Prevention-Surveillance and Epidemiology, and Intervention Research Svcs, National Center for HIV, STD, and TB Prevention; Div of AIDS, STD, and TB Laboratory Research, National Center for Infectious Diseases, CDC.

The findings in this report suggest a common source of HIV infection for at least 10 of 13 HIV-infected women who independently reported contact with the same partner. The high rate of HIV infection among sexual contacts of the putative index case-patient over a period of many months raises the possibility that efficient transmitters of HIV exist and may contribute disproportionately to HIV transmission.

Reasons for the apparently high attack rate (31%) among primary sex contacts in this cluster are unclear. Persons with primary HIV infection (i.e., within several weeks after infection)^2,3 or those in the late stage of HIV infection⁴ may be especially infectious because these periods are usually associated with high HIV viral loads (viremia). If the putative index case-patient was the common sex partner of these women, he probably was infected by or during February 1996 because the earliest date of last exposure for an HIV-infected primary contact was during February 1996. However, seven of 15 women whose first sexual exposure to the putative index case-patient was after September 1996 were HIV infected. These contacts probably would have been infected after the presumed period of primary HIV infection but before the late stage of HIV infection in the putative index case-patient.⁴ Thus, at least some HIV-infected persons, such as the putative index case-patient, may be highly infectious at times other than the primary or late stage of HIV infection.

Other characteristics may be critical in determining the likelihood of HIV transmission. Host susceptibility or infectiousness may increase as a result of inflammation or ulceration associated with STDs.⁵ For the susceptible partner, genital ulcerative infections (e.g., syphilis and HSV-2) are cofactors that facilitate transmission,⁵ but STDs were not significantly associated with being HIV-infected among the primary contacts in this cluster.

This cluster occurred despite other prevention successes in the county among youth.⁶ Discovery and evaluation of this cluster were possible, in part, because of the low background prevalence of HIV infection in the county⁶ (i.e., relatively few new cases of HIV infection could be detected and followed by public health personnel) and a coordinated response by health officials enabled prompt epidemiologic and laboratory investigations.

This cluster of infection has implications for HIV intervention and prevention. Unrecognized social and sexual networks of youth at high risk for HIV and other STDs exist even in rural areas where HIV prevalence is relatively low, and these networks can facilitate the rapid spread of HIV infection. It is important for public health programs to provide effective HIV prevention services to youth in rural areas.

References: 6 available

*Use of trade names and commercial sources is for identification only and does not imply endorsement by CDC or the U.S. Department of Health and Human Services.

MMWR. 1999;48:98-100

On August 31, 1998, two suspected cases of fungal pneumonia were reported to the Boulder County (Colorado) Health Department (BCHD). Both patients were immunocompetent, otherwise healthy adults working for the City of Boulder Open Space (CBOS) program on a prairie dog relocation project. This report summarizes the epidemiologic investigation by BCHD, the Colorado Department of Public Health and Environment, and CDC; the findings indicate that these two persons acquired blastomycosis in Colorado, which is outside the area where the disease is endemic.

On August 28, a 25-year-old man was admitted to a hospital with a 12-day history of fever, weight loss, fatigue, arthralgias, and productive cough. He had been treated by a private physician with two antibiotics during the preceding 8 days. On hospital admission, a computed tomography (CT) scan demonstrated bilateral pulmonary diffuse nodular opacities. A subsequent open lung biopsy revealed small budding yeasts. After 10 days of culture, Blastomyces dermatitidis was identified and confirmed by DNA probe (GenProbe, San Diego, California*), both at the local hospital laboratory and at CDC. The patient was treated with intravenous (IV) amphotericin B for 10 days, followed by a prescribed 6-month course of oral itraconazole.

On September 3, a 35-year-old man sought care for a 15-day history of fever, fatigue, shortness of breath, arthralgias, skin lesions (punctate lesions on arms and trunk and lesions resembling erythema nodosum on legs), cough, chest pain, and weight loss. His symptoms did not improve after 9 days of treatment with two antibiotics, and he was admitted to the same hospital as patient 1. A CT scan revealed diffuse, bilateral pulmonary nodules. The consulting physician for this patient also had seen patient 1; on the basis of work history and clinical course of the disease, the consultant suspected a fungal pneumonia. Specimens obtained by transbronchial biopsy/lavage were negative for fungal elements by microscopic examination and culture. Open lung biopsy specimens revealed small budding yeasts morphologically indistinguishable from those found in patient 1. Biopsy specimens grew B. dermatitidis after 21 days of culture. The patient received IV amphotericin B for 14 days, and at discharge, a 6-month prescribed course of oral itraconazole.

The two ill persons had worked together on the prairie dog relocation project on August 3 and 10 (14 and 7 days before onset of illness for patient 1). Work practices at the relocation site included using a gasoline-powered auger and hand trowels to excavate abandoned prairie dog tunnels and burrows that were being used by many other animal species. The workers did not use personal protective equipment (e.g., protective clothing or face masks). All 15 workers involved in the project were interviewed. The two ill persons had performed vigorous digging, created large amounts of dust, and spent 6-7 hours each day with their faces close to the dirt. It rained on 13 of the 15 days during July 22-August 5 (Colorado State University Climate Center, unpublished data, 1998); Boulder received 4.4 inches of rain during this period (normal rainfall for July and August combined is 3.3 inches).

The 15 workers were interviewed for symptoms of disease, and chest radiographs were offered to all workers; 12 (including the two ill workers) received chest radiographs. Only the two ill persons had chest abnormalities; both previously had lived in areas where the disease is endemic and where they could have been exposed to B. dermatitidis, but neither reported a history of such illness. Persons describing any symptoms of disease were referred to an occupational health specialist for further evaluation. Blood from 14 workers (including the two ill workers) was submitted for serologic testing (e.g., complement fixation, immunodiffusion, and radioimmunoassay)¹; results are pending. CDC collected composite soil samples from burrows at the site for microbiologic analyses²; results are pending.

DD Lenaway, PhD, AM Bailey, MS, Boulder County Health Dept; H Smith, MD, MA DeGroote, MD, Boulder Community Hospital, Boulder; K Gershman, MD, RE Hoffman, MD, State Epidemiologist, Div of Epidemiology, Colorado Dept of Public Health and Environment. National Institute for Occupational Safety and Health; Mycotic Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases; Div of Applied Public Health Training, Epidemiology Program Office; and an EIS Officer, CDC.

This article describes the first reported cases of blastomycosis acquired in Colorado. Blastomycosis is caused by inhalation of spores from B. dermatitidis, a dimorphic fungus found in soil and rotting wood. Blastomycosis most commonly presents as a subacute pulmonary disease, but the clinical spectrum ranges from asymptomatic infection to disseminated disease involving the skin, bones, and genitourinary system.^3,4 In the United States, disease occurs sporadically throughout the Ohio and Mississippi river valleys and the southeastern states.⁵ In states where blastomycosis is reportable (e.g., Wisconsin and Mississippi), the annual incidence of disease is 1.3-1.4 per 100,000 population; in areas where it is endemic, smaller areas of hyperendemicity can have rates of up to 41.9 cases per 100,000 persons.^6,7

In areas where blastomycosis is endemic, dogs infected with B. dermatitidis can signal increased risk for human infection.⁵ Few cases of blastomycosis have been reported among humans or animals in Colorado.^8,9 Although both patients in this outbreak previously resided in areas where they could have been exposed to B. dermatitidis, it is unlikely that they would have concurrent reactivation of previously acquired disease.

Two factors may have contributed to blastomycosis in the two workers described in this report. First, B. dermatitidis is more common in soils with high nitrogen and organic content, which may have been provided by the stored food and fecal matter of the animals living in the burrows.² Second, the above-average rainfall before the excavations may have been a factor, because humidity may aid reproduction of the organism.⁴

Blastomycosis should be considered in the differential diagnosis of illness in patients with subacute lobar or segmental pneumonia, particularly when it is refractory to initial antibiotic therapy and the patient has a history of outdoor occupational or recreational exposures. Serologic testing may assist in diagnosis, but complement fixation and immunodiffusion lack sensitivity and the WI-1 antigen-based antibody test has good sensitivity and specificity but is not widely available. Skin testing is not available for blastomycosis.⁴ Treatment of this disease includes ketoconazole or itraconazole for mild or moderate disease and intravenous amphotericin B for patients who are severely immunocompromised, have central nervous system involvement, or are severely ill.

The risk for exposure to blastomycosis remains small even in areas where the disease is endemic, and few public health recommendations have been developed for prevention of blastomycosis. Measures recommended for protecting workers against other endemic mycoses (e.g., histoplasmosis and coccidioidomycosis) probably will be protective against exposures to soil contaminated by B. dermatitidis.¹⁰ These measures include (1) use of a CDC-approved N-95 disposable half-facepiece filtering respirator (or equivalent) and protective clothing and shoe covers by all persons engaged in soil-disturbing activities during prairie dog relocation, (2) employer-provided instruction of all persons with potential to be engaged in these activities in the proper fitting and wearing of the recommended face mask, (3) implementation of a respiratory-protection program for employees, and (4) education of workers about clinical signs and symptoms of disease and screening and treatment options. Interim recommendations for workers engaged in prairie dog relocation have been developed by BCHD and will be modified as needed based on the serology and soil-testing results.

References: 10 available

*Use of trade names and commercial sources is for identification only and does not imply endorsement by CDC or the U.S. Department of Health and Human Services.