Mary J.R. Gilchrist

The Potential Role of Concentrated Animal Feeding Operations in Infectious Disease Epidemics and Antibiotic Resistance.

The industrialization of livestock production and the widespread use of nontherapeutic antimicrobial growth promotants has intensified the risk for the emergence of new, more virulent, or more resistant microorganisms. These have reduced the effectiveness of several classes of antibiotics for treating infections in humans and livestock. Recent outbreaks of virulent strains of influenza have arisen from swine and poultry raised in close proximity. This working group, which was part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating Hazards—Searching for Solutions, considered the state of the science around these issues and concurred with the World Health Organization call for a phasing-out of the use of antimicrobial growth promotants for livestock and fish production. We also agree that all therapeutic antimicrobial agents should be available only by prescription for human and veterinary use. Concern about the risk of an influenza pandemic leads us to recommend that regulations be promulgated to restrict the co-location of swine and poultry concentrated animal feeding operations (CAFOs) on the same site and to set appropriate separation distances.

Avian influenza among waterfowl hunters and wildlife professionals.

We report serologic evidence of avian influenza infection in 1 duck hunter and 2 wildlife professionals with extensive histories of wild waterfowl and game bird exposure. Two laboratory methods showed evidence of past infection with influenza A/H11N9, a less common virus strain in wild ducks, in these 3 persons.

Hepatitis E virus infection prevalence among selected populations in Iowa

BACKGROUND HEV causes an enteric infectious disease endemic in developing areas with hot climate. A case of endogenous HEV infection has been reported in the US. Recently, HEV-like virus was isolated from swine in Iowa. Swine production is a major industry in Iowa with the potential for human exposure to swine in and around industrial and family farm operations. OBJECTIVE The study objective was to determine whether individuals in Iowa are exposed to HEV. STUDY DESIGN Anti-HEV antibody prevalence in four selected Iowa populations was determined. Sera were collected from 204 patients with non-A, non-B, non-C hepatitis (non-A-C); 87 staff members of the Department of Natural Resources (DRN); 332 volunteer blood donors in 1989; and 111 volunteer blood donors in 1998. All sera were tested for anti-human HEV IgM and IgG by ELISA with confirmation of positivity by a peptide neutralization test. RESULTS Both the patients with non-A, non-B, non-C hepatitis (4.9%) and the healthy field workers from the Iowa DNR (5.7%) showed significantly higher prevalence of anti-HEV IgG antibodies compared to normal blood donor sera collected in 1998 (P < 0.05). CONCLUSIONS Human HEV or a HEV-like agent circulates in the Iowa geographical area. At-risk human populations with occupational exposure to wild animals and environmental sources of domestic animal wastes or with unexplained hepatitis have increased seroprevalence of HEV antibodies.

Comparison of seven kits for detection of rotavirus in fecal specimens with a sensitive, specific enzyme immunoassay

A sensitive, specific enzyme immunoassay (SSEIA) was compared to four commercial, enzyme-linked immunosorbent assay (ELISA) kits and three latex agglutination assay (LAA) kits: (1) Rotavirus EIA, International Diagnostic Laboratories (IDL), (2) Pathfinder, Kallestadt (KAL), (3) Rotavirus Bio-EnzaBead, Litton (LIT), (4) Rotazyme II, Abbott (RTZII), (5) Slidex Rota-Kit, bioMerieux (SRK), (6) Meritec-Rotavirus, Meridian (MER), and (7) Rotalex, Medical Technology Corporation (RLX). The SSEIA was chosen as the reference method due to its greater sensitivity in comparison to immunoelectron microscopy and polyacrylamide gel electrophoreses of viral RNA segments. Upon evaluation of 136 specimens (of which 44 were positive by SSEIA), the ELISA kits (LIT, KAL, IDL, and RTZII) had sensitivities of 80%, 98%, 91% and 84%; specificities of 95%, 78%, 100%, and 88%; positive predictive values (PPV) of 88%, 68%, 100%, and 77%; and negative predictive values (NPV) of 91%, 99%, 96%, and 92%. When compared with SSEIA, the three LAA tests (SRK, MER, and RLX) had sensitivities of 73%, 75%, and 62%; specificities of 99%, 93%, and 95%; PPVs of 97%, 85%, and 84%; and NPVs of 88%, 89%, and 84%. LAA test results appeared to be reliable, if positive, but the sensitivities of these tests were less than those of the ELISA tests. The ELISA tests that employed specimen specific negative controls were superior in minimizing false positive reactions.

Detection of Human Blood in the Bat Tick Carios (Ornithodoros) kelleyi (Acari: Argasidae) in Iowa

Abstract The argasid tick Carios (Ornithodoros) kelleyi Cooley & Kohls is a common ectoparasite of bats and has been found in massive numbers in homes with associated bat colonies in eastern Iowa. This tick feeds nearly exclusively on bats in nature. Several inhabitants of infested homes complained of “bug bites” at night while asleep that may have resulted in erythematous, edematous, urticaric skin lesions and constitutional signs and symptoms. We provide laboratory evidence that a single, engorged C. kelleyi nymph contained host blood from a human female. The clinical implications of our findings are intriguing but unclear.

Diagnostic analyses of biological agent-caused syndromes: laboratory and technical assistance

The impact of a bioterrorism attack can be greatly reduced by collaboration among primary healthcare providers, laboratories, the veterinary community, public health officials, and emergency response personnel. Improved communication and coordination are essential to make this happen. As a first-line provider, the emergency physician must keep in mind the possibility of bioterrorism and alert the laboratory so that samples can be processed in the correct fashion. New and exciting developments in laboratory organization, communication, and diagnostic capabilities will ensure that all patients receive the best possible care.

Polymerase chain reaction typing of nonviable Mycobacterium tuberculosis isolates

Repetitive element polymerase chain reaction (PCR) typing was applied to two Mycobacterium tuberculosis isolates for which both viable and nonviable cultures were available. DNA extracted from the nonviable cultures and from fresh subcultures of the viable cultures was amplified with primers directed against the insertion sequence IS6110 and the polymorphic GC-rich repetitive sequence. For both isolates, the nonviable cultures generated PCR-banding patterns identical to those generated by the fresh subcultures.