Inadequacy of IgM Antibody Tests for Diagnosis of Rocky Mountain Spotted Fever

McQuiston, Jennifer H.; Wiedeman, Caleb; Singleton, Joseph; Carpenter, Lisa; McElroy, Kristina; Mosites, Emily; Chung, Ida H.; Kato, Cecilia Y.; Morris, Kevin V.; Moncayo, Abelardo C.; Porter, Susan S.; Dunn, John R.

doi:10.4269/ajtmh.14-0123

Cited by 38 publications

(19 citation statements)

References 12 publications

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“…Some commercial laboratories also perform IFA assays and other serologic testing for IgM antibodies. However, IgM antibodies reactive with R. rickettsii are frequently detected in patients for whom no other supportive evidence of a recent rickettsiosis exists (285). IgM antibodies against ehrlichiae and A. phagocytophilum also might have lower specificity than IgG antibodies (286,287).…”

Section: Serologic Assaysmentioning

confidence: 99%

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Biggs¹,

Behravesh²,

et al. 2016

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Section: Serologic Assaysmentioning

confidence: 99%

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Biggs¹,

Behravesh²,

et al. 2016

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“…Previous studies have shown that after experimental infection, repeat inoculation with Rr elicits no clinical illness, hematological changes, or recall IgM response . Additionally, recrudescent infection with Rr is not thought to occur in dogs or humans . When inoculated with Rr , the 1 dog in this study ( Kat ) that was Rr seroreactive became clinically ill and had a robust IgM response, making it unlikely that she was previously infected with Rr .…”

Section: Discussionmentioning

confidence: 89%

Detection ofBartonellaspp. in dogs after infection withRickettsia rickettsii

Lashnits

Neupane

Maggi

et al. 2019

Veterinary Internal Medicne

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Background: Dynamics of infection by Bartonella and Rickettsia species, which are epidemiologically associated in dogs, have not been explored in a controlled setting. Objectives: Describe an outbreak investigation of occult Bartonella spp. infection among a group of dogs, discovered after experimentally induced Rickettsia rickettsii (Rr) infection. Animals: Six apparently healthy purpose-bred Beagles obtained from a commercial vendor.Methods: Retrospective and prospective study. Dogs were serially tested for Bartonella spp. and Rr using serology, culture, and PCR, over 3 study phases:3 months before inoculation with Rr (retrospective), 6 weeks after inoculation with Rr (retrospective), and 8 months of follow-up (prospective). Results: Before Rr infection, 1 dog was Bartonella henselae (Bh) immunofluorescent antibody assay (IFA) seroreactive and 1 was Rickettsia spp. IFA seroreactive. After inoculation with Rr, all dogs developed mild Rocky Mountain spotted fever compatible with low-dose Rr infection, seroconverted to Rickettsia spp. within 4-11 days, and recovered within 1 week. When 1 dog developed ear tip vasculitis with intra-lesional Bh, an investigation of Bartonella spp. infection was undertaken. All dogs had seroconverted to 1-3 Bartonella spp. between 7 and 18 days after Rr inoculation.

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“…While single IgG titers ≥1:64 likely overestimate rickettsial infection, for this study we felt sensitivity was more important in our surveillance case definitions than specificity [32]. We did not assess IgM serological results for laboratory diagnoses, since, unlike for other infectious diseases, IgM is not useful in identifying current or recent rickettsial infections [3,33,34]. We classified cases seropositive for both SFGR and TGR as unspecified Rickettsia infections (URI), since the potential cross-reactivity of the test makes it difficult to determine which group is the cause of the infection.…”

Section: Surveillance Case Classificationmentioning

confidence: 99%

Assessing human exposure to spotted fever and typhus group rickettsiae in Ontario, Canada (2013–2018): a retrospective, cross-sectional study

et al. 2020

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Background: Assessing the burden of rickettsial infections in Ontario, Canada, is challenging since rickettsial infections are not reportable to public health. In the absence of reportable disease data, we assessed the burden of rickettsial infections by examining patient serological data and clinical information. Methods: Our retrospective, cross-sectional study included patients who had Rickettsia serological testing ordered by their physician, in Ontario, from 2013 to 2018. We tested sera from 2755 non-travel patients for antibodies against spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) using an indirect immunofluorescence assay (IFA) (positive IgG titers ≥1:64). We classified cases using a sensitive surveillance case definition: confirmed (4-fold increase in IgG titers between acute and convalescent sera with clinical evidence of infection), possible (single positive sera with clinical evidence) and previous rickettsial infection (single positive sera without clinical evidence). We classified cases seropositive for both SFGR and TGR as unspecified Rickettsia infections (URIs). Results: Less than 5% of all patients had paired acute and convalescent sera tested, and of these, we found a single, laboratory-confirmed SFGR case, with a 4-fold increase in IgG titers and evidence of fever, maculopapular rash and headache. There were 45 possible (19 SFGR, 7 TGR, 19 URI) and 580 previous rickettsial infection (183 SFGR, 89 TGR, 308 URI) cases. The rate of positive tests for SFGR, TGR and URI combined (all case classifications) were 4.4 per 100,000 population. For confirmed and possible cases, the most common signs and symptoms were fever, headache, gastrointestinal complaints and maculopapular rash. The odds of having seropositive patients increased annually by 30% (odds ratio = 1.3, 95% confidence interval: 1.23-1.39).

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Inadequacy of IgM Antibody Tests for Diagnosis of Rocky Mountain Spotted Fever

Cited by 38 publications

References 12 publications

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Detection ofBartonellaspp. in dogs after infection withRickettsia rickettsii

Assessing human exposure to spotted fever and typhus group rickettsiae in Ontario, Canada (2013–2018): a retrospective, cross-sectional study

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