Sensitivity of Lyme Borreliosis Spirochetes to Serum Complement of Regular Zoo Animals: Potential Reservoir Competence of Some Exotic Vertebrates

Abstract

Reaction of vertebrate serum complement with different Borrelia burgdorferi sensu lato species is used as a basis in determining reservoir hosts among domesticated and wild animals. Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii were tested for their sensitivity to sera of exotic vertebrate species housed in five zoos located in the Czech Republic. We confirmed that different Borrelia species have different sensitivity to host serum. We found that tolerance to Borrelia infection possessed by hosts might differ among individuals of the same genera or species and is not affected by host age or sex. Of all zoo animals included in our study, carnivores demonstrated the highest apparent reservoir competency for Lyme borreliosis spirochetes. We showed that selected exotic ungulate species are tolerant to Borrelia infection. For the first time we showed the high tolerance of Siamese crocodile to Borrelia as compared to the other studied reptile species. While exotic vertebrates present a limited risk to the European human population as reservoirs for the causative agents of Lyme borreliosis, cases of incidental spillover infection could lead to successful replication of the pathogens in a new host, changing the status of selected exotic species and their role in pathogen emergence or maintenance. The question if being tolerant to pathogen means to be a competent reservoir host still needs an answer, simply because the majority of exotic animals might never be exposed to spirochetes in their natural environment.

Tick Thioester-Containing Proteins and Phagocytosis Do Not Affect Transmission of Borrelia afzelii from the Competent Vector Ixodes ricinus

“…Complement systems in sera of various vertebrate animals exhibit different borreliacidal effects against different Borrelia genospecies (Kurtenbach et al, 2002; Bhide et al, 2005; Ticha et al, 2016). Because Ixodes sp.…”

“…We have previously reported that ticks possess molecules related to components of the mammalian complement system (Buresova et al, 2011; Kopacek et al, 2012; Urbanova et al, 2015) and therefore we questioned whether tick cell-free plasma can exhibit lytic activity against Borrelia , as demonstrated for a variety of vertebrate animals (Kurtenbach et al, 1998, 2002; Kuo et al, 2000; Bhide et al, 2005; De Taeye et al, 2013; Ticha et al, 2016). The results shown in the Figure 1 clearly demonstrate that there is almost no effect of I. ricinus plasma against cultivated spirochetes compared to bovine serum, which is known to have strong complement-mediated borreliacidal activity (Kurtenbach et al, 1998; Bhide et al, 2005).…”

Pleomorphism and Viability of the Lyme Disease Pathogen Borrelia burgdorferi Exposed to Physiological Stress Conditions: A Correlative Cryo-Fluorescence and Cryo-Scanning Electron Microscopy Study

“…Serum samples from male African buffalo ( Syncerus cifer ) and female impala ( Aepyrecoros melampus ) were obtained from the zoo in Hradec Kralove (Czech Republic; Tichá et al, 2016). Blood samples were taken during routine checks of the animals, following zoo ethics regulations.…”

“…We used either sera from impala ( Aepyceros melampus ) or African buffalo ( Syncerus cifer ), that were determined in our earlier work to exert different bacteriolytic activities against spirochetes (Tichá et al, 2016). Impala serum revealed the strongest borreliacidal effect against all tested spirochete species from the B. burgdorferi s.l.…”

“…Impala serum revealed the strongest borreliacidal effect against all tested spirochete species from the B. burgdorferi s.l. complex in the complement sensitivity test, whereas buffalo serum did not display any borreliacidal effect (Tichá et al, 2016). …”