Humanpathogene Rickettsien in Zecken des östlichen Sambias
Kattner, Simone; Küpper, Thomas (Thesis advisor); Apel, Christian (Thesis advisor)
Düren : Shaker Verlag (2020)
Book, Dissertation / PhD Thesis
In: Aachener Schriftenreihe zur Präventivmedizin 4
Page(s)/Article-Nr.: VI, 94 Seiten : Illustrationen
Ticks are important vectors for Rickettsia spp. of the Spotted Fever Group in the world. Tick transmitted Rickettsioses are common in sub-Saharan countries. Especially Rickettsia africae, which causes African tick-bite fever in humans, is a wide-spread pathogen in sub-Saharan Africa. Rickettsioses pose an underestimated risk to tourists’ and locals’ health. Rickettsioses are far more common in ill returning travelers than malaria. There is evidence of Rickettsia spp. in Zambia, but so far there is a significant lack of data. A total of 1,465 ticks were collected in 20 different locations: 1,438 from dogs, 24 from cattle and 3 from one cat. Ticks were identified by morphological features or by sequencing of the 16S rRNA gene. Individual ticks were tested for rickettsia using a pan-Rickettsia real-time-PCR. Rickettsia species were further identified by sequencing the 23S-5S intergenic spacer region, partial ompA or ompB gene, respectively. Three different tick genera and seven tick species were found: 30 Amblyomma variegatum, 29 Haemaphysalis elliptica, 1 Rhipicephalus Boophilus microplus, 5 Rhipicephalus zambesiensis, 9 Rhipicephalus simus, 136 Rhipicephalus appendiculatus and 1,255 Rhipicephalus sanguineus “tropical lineage”. Of the 1,465 collected ticks, 67 (4.6 %) were tested positive in the pan-Rickettsia PCR. Rickettsia africae was identified in 24 A. variegatum and in three Rh. sanguineus “tropical lineage” by PCR. Rickettsia massiliae was detected in one Rh. sanguineus “tropical lineage”. Rickettsia conorii ssp. caspia was found in one Rh. sanguineus “tropical lineage”. Another 36 specimens were positive in pan-Rickettsia PCR but identification of the respective species was impossible due to low rickettsia DNA content. The majority (83.3 %) of the A. variegatum tested positive for R. africae. R. africae showed gentical variability in 23S-5S gene and ompA fragment IV, which could have an impact on pathogenic features. This study proves the presence of Rickettsia species in South Luangwa Valley, Eastern Province, Zambia. Rickettsia africae, R. massiliae and R. conorii ssp. caspia, human pathogens causing spotted fever, were found. Therefore, health advice for tourists travelling to Zambia should include tick protection strategies. Rickettsiosis should be considered for differential diagnosis in travelers returning ill from Zambia.