Central Nervous System Dysfunction Associated With Rocky Mountain Spotted Fever Infection in Five Dogs

2005 ◽  
Vol 41 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Jessica S. Mikszewski ◽  
Charles H. Vite
Keyword(s):  
Spotted Fever ◽  
Fluorescent Antibody ◽  
Clinical Signs ◽  
Rocky Mountain ◽  
Rocky Mountain Spotted Fever ◽  
Rickettsia Rickettsii ◽  
Neurological Signs ◽  
Central Nervous System Dysfunction ◽  
Enzyme Screening ◽  
Time Of Presentation

Five dogs from the northeastern United States were presented with clinical signs of neurological disease associated with Rocky Mountain spotted fever (RMSF) infection. Four of the five dogs had vestibular system dysfunction. Other neurological signs included paresis, tremors, and changes in mentation. All of the dogs had an elevated indirect fluorescent antibody titer or a positive semiquantitative enzyme screening immunoassay titer for Rickettsia rickettsii at the time of presentation. Although a higher mortality rate has been reported for dogs with neurological symptoms and RMSF infection, all of the dogs in this study improved with appropriate medical therapy and supportive care.

Canine Rocky Mountain Spotted fever: a retrospective study of 30 cases

2001 ◽  
Vol 37 (1) ◽  
pp. 41-48 ◽  
Author(s):  
AM Gasser ◽  
AJ Birkenheuer ◽  
EB Breitschwerdt
Keyword(s):  
Antibody Titer ◽  
Spotted Fever ◽  
Clinical Signs ◽  
Rocky Mountain ◽  
Neurological Dysfunction ◽  
Rocky Mountain Spotted Fever ◽  
Cutaneous Lesions ◽  
Laboratory Findings ◽  
Antibody Titers ◽  
Time Of Presentation

Rocky Mountain spotted fever (RMSF) was diagnosed in 30 dogs examined at North Carolina State University, Veterinary Teaching Hospital between 1984 and 1997. Historical, physical examination, and laboratory abnormalities were reviewed. Diagnostic criteria included a four-fold rise in antibody titer to Rickettsia rickettsii (R. rickettsii) (n=15) or a single R. rickettsii antibody titer of 1:1,024 or greater (n=15; when this initial titer was determined one week or more after the onset of clinical signs). Fifteen (50%) dogs were greater than seven years of age, and 13 (43%) dogs were between two and seven years of age. There was no sex predilection. Only five (17%) dogs had a history of known tick exposure. Presumably due to delayed diagnosis, dogs with antibody titers of 1:1,024 or greater at the time of presentation had a higher incidence of more severe neurological dysfunction (e.g., ataxia, hyperesthesia, vestibular disease, and seizures) and cutaneous lesions (e.g., hyperemia, edema, petechiae, ecchymoses, and necrosis). Laboratory findings included anemia, leukocytosis accompanied by toxic granulation of neutrophils, hypoalbuminemia, and coagulation abnormalities; signs were generally more severe in the 15 dogs with R. rickettsii antibody titers of 1:1,024 or greater at the time of presentation. Twelve (40%) dogs in this study were severely thrombocytopenic (less than 75 x10(3) platelets/microl; reference range, 200 to 450 x 10(3)/microl), without clinical evidence of fulminant disseminated intravascular coagulation. In this study, the survival rate following R. rickettsii infection was 100%.

Spotted fever group rickettsiae in immature and adult ticks (Acari: Ixodidae) from a focus of Rocky Mountain spotted fever in Connecticut

1985 ◽  
Vol 31 (12) ◽  
pp. 1131-1135 ◽  
Author(s):  
Louis A. Magnarelli ◽  
John F. Anderson ◽  
Willy Burgdorfer ◽  
Robert N. Philip ◽  
W. Adrian Chappell
Keyword(s):  
Spotted Fever ◽  
Fluorescent Antibody ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Etiologic Agent ◽  
Ixodid Ticks ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Serum Samples ◽  
Rickettsia Rickettsii

Immature and adult ixodid ticks were collected during 1983 and 1984 in Newtown, Connecticut, an area endemic for Rocky Mountain spotted fever (RMSF), to determine prevalence of infection by spotted fever group (SFG) rickettsiae. Direct fluorescent-antibody (FA) staining revealed SFG organisms in 6 (1.8%) of 332 Dermacentor variabilis larvae, 5 (7.8%) of 64 D. variabilis nymphs, and in 2 (40%) of 5 Ixodes cookei nymphs removed from small- and medium-sized mammals. Hemolymph tests detected rickettsia-like organisms in 15 (8.8%) of 170 D. variabilis adults; 8 specimens retested by direct FA were negative. In contrast, hemocytes from 5 (8.6%) of 58 Ixodes texanus females contained organisms that stained positively in both hemolymph and direct FA tests. An indirect microimmunofluorescence test identified specific antibodies to Rickettsia rickettsii, the etiologic agent of RMSF, in serum samples from a chipmunk, raccoons, and white-footed mice. Results indicate that immature or adult ticks of at least three species may be involved in the maintenance and transmission of SFG rickettsiae at Newtown.

Mitbringsel aus den Ferien

Praxis ◽  
2005 ◽  
Vol 94 (47) ◽  
pp. 1869-1870
Author(s):  
Balestra ◽  
Nüesch
Keyword(s):  
Rocky Mountains ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Rickettsia Conorii ◽  
Rocky Mountain Spotted Fever ◽  
Klinische Diagnose ◽  
Rickettsia Rickettsii

Eine 37-jährige Patientin stellt sich nach der Rückkehr von einer Rundreise durch Nordamerika mit einem Status febrilis seit zehn Tagen und einem makulösem extremitätenbetontem Exanthem seit einem Tag vor. Bei suggestiver Klinik und Besuch der Rocky Mountains wird ein Rocky Mountain spotted fever diagnostiziert. Die Serologie für Rickettsia conorii, die mit Rickettsia rickettsii kreuzreagiert, war positiv und bestätigte die klinische Diagnose. Allerdings konnte der beweisende vierfache Titeranstieg, möglicherweise wegen spät abgenommener ersten Serologie, nicht nachgewiesen werden. Nach zweiwöchiger antibiotischer Therapie mit Doxycycline waren Status febrilis und Exanthem regredient.

scholarly journals Solution structure of the cold-shock-like protein fromRickettsia rickettsii

2012 ◽  
Vol 68 (11) ◽  
pp. 1284-1288 ◽  
Author(s):  
Kyle P. Gerarden ◽  
Andrew M. Fuchs ◽  
Jonathan M. Koch ◽  
Melissa M. Mueller ◽  
David R. Graupner ◽  
...  
Keyword(s):  
Solution Structure ◽  
Cold Shock ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Rocky Mountain Spotted Fever ◽  
Cold Shock Proteins ◽  
Rickettsia Rickettsii ◽  
The Family ◽  
Α Helix ◽  
Shock Proteins

Rocky Mountain spotted fever is caused byRickettsia rickettsiiinfection.R. rickettsiican be transmitted to mammals, including humans, through the bite of an infected hard-bodied tick of the family Ixodidae. Since theR. rickettsiigenome contains only one cold-shock-like protein and given the essential nature of cold-shock proteins in other bacteria, the structure of the cold-shock-like protein fromR. rickettsiiwas investigated. With the exception of a short α-helix found between β-strands 3 and 4, the solution structure of theR. rickettsiicold-shock-like protein has the typical Greek-key five-stranded β-barrel structure found in most cold-shock domains. Additionally, theR. rickettsiicold-shock-like protein, with a ΔGof unfolding of 18.4 kJ mol−1, has a similar stability when compared with other bacterial cold-shock proteins.

scholarly journals Prednisolone at anti-inflammatory or immunosuppressive dosages in conjunction with doxycycline does not potentiate the severity of Rickettsia rickettsii infection in dogs.

1997 ◽  
Vol 41 (1) ◽  
pp. 141-147 ◽  
Author(s):  
E B Breitschwerdt ◽  
M G Davidson ◽  
B C Hegarty ◽  
M G Papich ◽  
C B Grindem
Keyword(s):  
Spotted Fever ◽  
Rocky Mountain ◽  
Rocky Mountain Spotted Fever ◽  
Serum Samples ◽  
Concurrent Administration ◽  
Rickettsia Rickettsii ◽  
Beneficial Effects ◽  
Concurrent Use ◽  
Antibody Titers ◽  
Anti Inflammatory

Dogs were experimentally inoculated with Rickettsia rickettsii to determine if anti-inflammatory or immunosuppressive dosages of prednisolone, when administered in conjunction with an antirickettsial antibiotic (doxycycline), induced therapeutically relevant pathophysiological consequences that ultimately influence disease outcome. Although the duration of rickettsemia was prolonged in dogs receiving immunosuppressive, but not anti-inflammatory, corticosteroids, concurrent administration of doxycycline and corticosteroids conferred no other detected detrimental effects. Treatment with doxycycline or doxycycline in conjunction with prednisolone resulted in decreased R. rickettsii-specific antibody titers; however, examination of appropriately timed acute- and convalescent-phase serum samples would have facilitated an accurate diagnosis of Rocky Mountain spotted fever (RMSF) in all 16 dogs. We conclude that the concurrent use of anti-inflammatory or immunosuppressive doses of prednisolone in conjunction with doxycycline, early in the course of experimental RMSF, confers no clinically relevant detrimental effects and that additional studies might be indicated to detect possible beneficial effects in cases of severe or potentially fulminant RMSF. However, because the illness induced in these dogs was of mild to moderate severity, the results of this study should definitely not be construed as supporting the safety or efficacy of prednisolone for treatment of severe canine or human RMSF.

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