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ANALYSIS OF IRAQI SERUM SAMPLES 14 DEC 90 Filename:0500br.95 SUBJECT: ANALYSIS OF IRAQI SERUM SAMPLES 14 DEC 90 GENERAL: 1. The data and resulting analysis/conclusions that can be made from these serum specimens are inconclusive and at best presumptuous. From an epidemiological perspective, the primary factors limiting the value of these serological results include, a. Lack of demographic information from Iraqi personnel. b. Absence of sero-surveys of endemic diseases in indigenous personnel. c. Small number of samples. d. Break in chain-of-custody of the samples. (How sure are we that these are really Iraqi specimens?) 2. The positive Iraqi samples conform to plausible expectations resulting from natural exposure to endemic disease agents or non- specific cross reactions. It is unlikely that the positive reactions are due to immunizations. Two agents warrant additional comments. a. Coxiella burnetii (Q Fever): The agent is considered to be widely distributed throughout the region; serological studies suggest that it is highly endemic/enzootic in eastern Saudi Arabia, and it is probably endemic/enzootic in Iraq at similar levels. Sporadic cases have been reported areawide, but incidence is suspected to be greater than reported due to limited diagnostic capabilities. Serology from indigenous personnel in rural areas in Saudi Arabia indicates that subClinical infection develops in Childhood, and virtually all young adults have had sensitizing contact (inducing acquired immunity). Due to similar epidemiologic characteristics, adding tests for Brucella spp. antigens would improve the confidence of the analysis suggesting that the positive titers are from natural exposure. b. Sandfly Fever: Both the Sicilian and Naples strains are highly endemic in Iraq and the Positive results represent natural exposure. RECOMMENDATIONS FOR FUTURE SAMPLE TESTING AND REPORTING: [ (b)(1) sec 1.3(a)(4) ] [ (b)(6) ] ANALYSIS OF IRAQI SERUM SAMPLES SPECIMEN DESCRIPTION Serum specimens were collected from 20 Iraqi personnel [ (b)(1) sec 1.3(a)(4) ]. Histories for the Iraqi population were not provided; the information may be furnished at a later date. Serum specimens previously collected from American troops in Saudi Arabia were used as control samples for comparison. ANALYSIS PERFORMED The sera were screened for antibody against the likely biological warfare agents Bacillus anthracis and botulinum toxin. The samples were also screened for Coxiella burnetii, Francisella tularensis, Yersinia Pestis, Venezuela equine encephalitis virus, and Crimean Congo hemorrhagic fever virus reactive antibodies and serological evidence of the naturally occurring diseases murine typhus, Chlamydia pneumonia, Rift Valley fever, West Nile fever, and sandfly fever. CONCLUSIONS The results do not show convincing evidence that the few Iraqi troops tested have been vaccinated against anthrax or the botulinum toxins. The reactions with the "protective antigen" from Bacillus anthracis are low-level and may indicate prior natural exposures to anthrax or possibly a non-specific reaction. Tests are being performed to confirm this result. Tests are also being performed to detect very low levels of antibodies to botulinum toxin, such as might occur after administration of a poor vaccine. Several of the Iraqi troops seem to have had natural infections caused by Coxiella burnetii, Francisella tularensis, Rickettsia typhi, and sandfly fever viruses, or serologically cross-reacting agents. The presence of IGM reactive antibody in several of the specimens may suggest recent infections. The presence of Yersinia Pestis reactive antibody among a few of the American troops suggests a previous vaccination history or a natural exposure to plague. A small number of the Americans demonstrated antibody levels indicating little or no previous exposure to most of the agents. RECOMMENDATIONS [ (b)(1) sec 1.3(a)(4) ] TECHNICAL RESULTS The results of the serological tests are presented in the accompanying table. These answers were generated with the best available rapid serological assays. Conclusive data, particularly for low-level antibody titers, may require traditional serological methods which need large volumes of sera and several days to complete. 1. 3/20 Iraqi and 3/20 American samples reacted with Bacillus anthracis antigen. These seropositives react at low titers with "protective antigen" but not "lethal factor". 2. None of the Iraqi samples tested reacted convincingly with the botullnum toxins: 20 samples were tested with type A toxin; 19 samples with type B or C toxins; and 18 samples type D, E, or F toxins. The American specimens were not tested. 3. 11/18 Iraqi and 0/20 American samples were Coxiella burnetii antibody positive. 5/18 Iraqi samples were IGM and 6/18 Iraqi samples were IGG positive. 4. No definite positives were observed; 9/18 Iraqi and 5/20 American samples reacted weakly with Francisella tularensis antigens. 4/18 Iraqi samples were IGM and 5/18 Iraqi samples were IGG weak reactions. 1/20 American samples were IGM and 4/20 American samples were IGG weak reactions. 5. 0/20 Iraqi and 5/20 American samples were Yersinia Pestis antibody positive. 6. 0/16 Iraqi and 0/20 American samples were Venezuela equine encephalitis virus antibody positive. 7. 1/16 Iraqi and 1/20 American samples were Crimean Congo hemorrhagic fever virus antibody positive. 8. No definite positives were observed; 10/18 Iraqi and 10/20 American samples reacted weakly with Rickettsia tYphi antigens. 7/18 Iraqi samples were IGM and 3/18 Iraqi samples were IGG weak reactions. 9/20 American samples were IGM and 1/20 American samples were IGG weak reactions. 9. No definite positives were observed; 5/18 Iraqi and 3/20 American samples reacted weakly with Chlamydia Pneumoniae antigens. 3/18 Iraqi samples were IGM and 2/18 Iraqi samples were IGG weak reactions. 1/20 American samples were IGM and 2/20 American samples were IGG weak reactions. 10. 0/16 Iraqi and 1/20 American samples were Rift Valley fever virus antibody positive. 11. 1/16 Iraqi and 1/20 American samples were West Nile virus antibody positive. 12. 13/16 Iraqi and 0/20 American samples were sandfly fever virus (Sicilian strain) antibody positive. 13. 7/16 Iraqi and 1/20 American samples were sandfly fever virus (Naples strain) antibody positive. ANTIBODY FREQUENCY IN SERA FROM IRAQI AND AMERICAN PERSONNEL No. Antibodv Positive/Total Tested (a) Aqent Iraqi Specimens American Specimens Bacillus anthracis 3/20 3/20 Protective Antigen 3/20 3/20 Lethal Factor 0/20 0/20 Botulinum toxin: Type A 0/20 ND (b) Type B 0/19 ND TYPE C 0/19 ND TYPE D 0/18 ND TYPE E 0/18 ND TYPE F 0/18 ND Coxiella burnetii 11/18 0/20 Francisella tularensis (c) 0/18 0/20 Yersinia pestis 0/20 5/20 Venezuela equine 0/16 0/20 encephalitis virus Crimean Congo hemorrhagic 1/16 1/20 fever virus Rickettsia tyPhi (c) 0/18 0/20 Chlamydia pneumoniae (c) 5/18 3/20 Rift Valley fever virus 0/16 1/20 West Nile virus 1/16 1/20 Sandfly fever virus 13/16 0/20 (Sicilian strain) Sandfly fever virus 7/16 1/20 (Naples strain) (a) Total number of sera tested was dependent upon sample availability. (b) Not Done. (c) Several sera had low-level reactions of doubtful significance and are under further study.
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