Seroreactivity for spotted fever rickettsiae and co-infections with other tick-borne agents among habitants in central and southern Sweden

Abstract

Patients seeking medical care with erythema migrans or flu-like symptoms after suspected or observed tick bite in the southeast of Sweden and previously investigated for Borrelia spp. and/or Anaplasma sp. were retrospectively examined for serological evidence of rickettsial infection (Study 1). Twenty of 206 patients had IgG and/or IgM antibodies to Rickettsia spp. equal to or higher than the cut-off titre of 1:64. Seven of these 20 patients showed seroconversion indicative of recent or current infection and 13 patients had titres compatible with past infection, of which five patients were judged as probable infection. Of 19 patients with medical records, 11 were positive for Borrelia spp. as well, and for Anaplasma sp., one was judged as positive. Five of the 19 patients had antibodies against all three pathogens. Erythema migrans or rash was observed at all combinations of seroreactivity, with symptoms including fever, muscle pain, headache and respiratory problems. The results were compared by screening an additional 159 patients (Study 2) primarily sampled for the analysis of Borrelia spp. or Mycoplasma pneumoniae. Sixteen of these patients were seroreactive for Rickettsia spp., of which five were judged as recent or current infection. Symptoms of arthritis, fever, cough and rash were predominant. In 80 blood donors without clinical symptoms, approximately 1 % were seroreactive for Rickettsia spp., interpreted as past infection. The study shows that both single and co-infections do occur, which illustrate the complexity in the clinical picture and a need for further studies to fully understand how these patients should best be treated.

Prevalence of Rickettsia spp. in Ticks and Serological and Clinical Outcomes in Tick-Bitten Individuals in Sweden and on the Åland Islands

“…The latter may be of importance in explaining why participants with a recent or current co-infection with Borrelia spp. and Rickettsia spp., based on seroconversion, were fewer in the present study compared to findings from earlier studies where co-infection was based on sero-reactivity [18, 20]. …”

“…helvetica -infected Vero cells supplemented with 10% yolk sac solution were used as antigen. The antigen solution was applied to each well of the microscope slides, dried, and fixed in acetone, where after the serum was serially diluted in titres 1/64, 1/128 and 1/256, respectively, and incubated as previously described [18]. Human blood donor serum was used as a negative control, and serum from a patient with proven end-point titres of 1:256 and 1:128 of IgG/IgM, respectively, was used as a positive control.…”

“…In a study from Italy, the most frequently observed double infestation in ticks was SFG Rickettsiae and Borrelia burgdorferi sensu lato [17]. Despite the fact that several agents appear in ticks, co-infections in humans have rarely been studied, although a few surveys have been conducted that included co-infections with different Rickettsia species [18–23]. …”

African tick bite fever in returning Swedish travellers. Report of two cases and aspects of diagnostics

“…[15,16] IgG titres ≥128 and/or IgM titres ≥ 64, and/or a fourfold increase in two sera within a 2–4 week interval are considered indicative of infection by Rickettsia spp., if homologous antigens are used in the IFA test. When a heterologous antigen is used, a step lower titre may also be indicative of infection.…”

Prevalence of Tick Borne Haemoparasites in Some Breeds of Cattle and Goats Slaughtered in Some Abattoirs within Makurdi, Nigeria

“…The tick-borne disease may be triggered by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses and Protozoa. Because ticks can harbour more than one disease-causing agent, cattle and goats can be infected with more than one pathogen at the same time [4]. Ticks and the diseases they transmit are responsible for severe losses caused either by tick worry, blood loss, bloodrelated infections, damage to hides, udders and the transmission of toxins by the diseases they transmit.…”