Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Within South Africa (SA) parasites have received variable attention with limited research conducted on mites within the family Trombiculidae. They are regarded as temporary parasites with only the larval stage or “chigger” being parasitic. The present study investigated the diversity, ecology and distribution of chiggers associated with small mammal hosts (rodents and insectivores) across SA, with a focus on the Cape Floristic Region (CFR). The study supports the existence of seasonal occurrence of chiggers in a temperate region. Chiggers that occurred on a generalist rodent host were most prevalent during the warm dry months of the year as opposed to wet cold months. Total counts conducted on the bodies of several co-occurring rodent species in the CFR recorded a diverse assemblage of chigger species. The findings support previous studies in that chiggers are host generalist, though there does appear to be a preference for the most abundant host species, Rhabdomys pumilio, in the biotype. Host species were parasitized by multiple chigger species of which Leptotrombidium muridium was the most abundant species. The study recorded and described three new chigger species (Austracarus n. sp., Microtrombicula n. sp. and Schöngastiella n. sp.). Chigger abundances were found to be higher on reproductively active as opposed to non-active hosts. Twelve chigger species were recorded across SA and the individual species showed variation in extent of their geographic range. On-host distribution of chigger species recorded a preference for the tail area of the host, which was shared by the three most abundant chigger species. This pattern may explain the higher co-occurrence of chigger species than expected by chance that was recorded on R. pumilio. It is evident that chiggers of small mammals are a diverse group that vary spatially and temporary across the landscape. / AFRIKAANSE OPSOMMING: Die verskeie parasiet taksa wat in Suid Afrika (SA) voorkom het ongelyke aandag ontvang tydens parasitologie studies tot dusver. Trombiculidae myte is een van die parasiet groepe wat baie min aandag ontvang het. Die groep myte word beskou as tydelike parasiete, weens die feit dat slegs die larf stadium (ook verwys as “chigger”) van die myt parasities is. Die studie het die diversiteit, ekologie en geografiese verspreiding van chiggers bestudeer wat geassosieer word met klein soogdiere binne SA, met ‘n fokus op die Kaapse Floristiese Ryk (KFR). Die studie het bevind dat chiggers ‘n seisoenale voorkoms het, hul was meer volop tydens die warm droë maande in vergelyking met nat en koel winter maande, soortgelyke resultate is aangeteken in ander dele van die wêreld. Die studie het ook gevind dat die myte wat in die KFR nie gasheer spesifiek was nie, maar dat hul wel ‘n voorkeur getoon het vir die gasheer wat die volopste was, Rhabdomys pumilio. Die verskeie gasheer spesies wat ondersoek was was deur verskillende chigger spesies geparasiteer waarvan Leptotrombidium muridium die mees volopste was. Drie nuwe chigger spesies is beskryf tydens die studie (Austracarus n. sp., Microtrombicula n. sp. and Schöngastiella n. sp.). Die resultate van die studie het ook gedui dat gashere wat reproduktief was hoër getalle myte gehad het wat op hul geparasiteer het in vergelyking met gashere wat nog nie reproduktief aktief was nie. Twaalf chigger spesies was tydens die studie aangeteken, hul het verskil in terme van hul geografiese verspreidings. Die verspreiding van die myte op die gasheer se lyf was ook bestudeer en daar was bevind dat die myte ‘n voorkeur toon vir die stert area van die gasheer. Die verskillende chigger spesies het ook saam voorgekom op ‘n spesifieke aanhegtings plek op die muis se lyf en geen uitsluitings-kompetisie was gevind nie. Die gevolgtrekking van die studie is dat chiggers wat klein soogdiere parasiteer in SA ‘n baie diverse groep is wat verskil ten opsigte van hul geografiese verspreiding asook in terme van in hul seisoenale teenwoordigheid binne die landskap.

Brazil has 58 species of chigger mites parasitizing different animal groups. Of these, only 6 species were reported for birds, being 1 of Apolonia, 2 of Eutrombicula, 1 of Neoschoengastia and 2 of Parasecia. The larvae of chiggers cause deep lesions and cutaneous reactions in the host, and are often cited as vectors of pathogens. In the United States, public health departments have come across the need for cataloging and knowledge of the biology of these mites as potential vectors of Rickettsia spp. In Brazil, the first cases of Brazilian Macular Fever (BMF) diagnosed in São Paulo were associated with these mites because they were found in outbreaks of the disease. However, its role in the epidemiology of rickettsial disease has not been confirmed. Another concern is dermatitis caused by the bite of these mites, popularly known as trombiculiasis. As it is well known, thrombiculid mites are not specific and several cases of bites in humans have been reported. Thus, the purpose of the present study is to know the current situation of chigger mites parasitizing birds, to clarify aspects of its taxonomic complexity, as well as to provide information about its participation in the epidemiology of Rickettsia in some localities in the southeastern region of the country. From the material examined in the present study were identified 8 species: Blankaartia shatrovi n. sp., Blankaartia sinnamaryi, Microtrombicula n. sp., Eutrombicula tinami, Eutrombicula goeldii, Parasecia n. sp.1, Parasecia n. sp.2, Parasecia n. sp.3. The mites were kept in absolute alcohol, were submitted to DNA extraction and investigation of the presence of Rickettsia. One of the samples showed 100% for Rickettsia felis. Therefore, for Brazil now, we have 13 species described for the entire national territory, with the exception of the Midwest region, and, in addition, the first record of the presence of Rickettsia in chigger mites on South America. / O Brasil possui 58 espécies de ácaros trombiculídeos parasitando diferentes grupos animais. E destas, somente 6 espécies foram reportadas para aves, sendo 1 de Apolonia, 2 de Eutrombicula, 1 de Neoschoengastia e 2 de Parasecia. As larvas de trombiculídeos provocam lesões profundas e reações cutâneas no hospedeiro, sendo por muitas vezes citados como vetores de agentes patogênicos. Nos Estados Unidos, os departamentos de saúde pública se depararam com a necessidade de catalogação e conhecimento da biologia desses ácaros por serem considerados potenciais vetores de Rickettsia spp. No Brasil, os primeiros casos de Febre Maculosa Brasileira (FMB) diagnosticados em São Paulo, foram associados a esses ácaros porque terem sido encontrados em focos da doença. No entanto, o seu papel na epidemiologia da riquetsiose não foi confirmado. Outra preocupação é a dermatite causada pela mordida desses ácaros, popularmente conhecida como trombiculíase. Como é bem conhecido, trombiculídeos não são específicos e vários casos de mordidas em humanos já foram relatados. Dessa forma, a proposta do presente estudo é conhecer a situação atual dos trombiculídeos de aves, esclarecer os aspectos de sua complexidade taxonômica, bem como fornecer informações sobre sua participação na epidemiologia de riquétsias em algumas localidades da região sudeste do país. Do material examinado no presente estudo foram identificadas 8 espécies: Blankaartia shatrovi sp. n., Blankaartia sinnamaryi, Microtrombicula sp. n., Eutrombicula tinami, Eutrombicula goeldii, Parasecia sp. n.1, Parasecia sp. n.2, Parasecia sp. n.3. Os ácaros mantidos em álcool absoluto foram submetidos à extração de DNA e investigação da presença de Rickettsia. Uma das amostras aprentou 100% para Rickettsia felis. Portanto, para o Brazil agora, temos 13 espécies descritas para todo o território nacional, com excessão da região Centro-Oeste, e, além disso, o primeiro registro da presença de Rickettsia em ácaros trombiculídeos da América do Sul.

Brazil has 58 species of chigger mites parasitizing different animal groups. Of these, only 6 species were reported for birds, being 1 of Apolonia, 2 of Eutrombicula, 1 of Neoschoengastia and 2 of Parasecia. The larvae of chiggers cause deep lesions and cutaneous reactions in the host, and are often cited as vectors of pathogens. In the United States, public health departments have come across the need for cataloging and knowledge of the biology of these mites as potential vectors of Rickettsia spp. In Brazil, the first cases of Brazilian Macular Fever (BMF) diagnosed in São Paulo were associated with these mites because they were found in outbreaks of the disease. However, its role in the epidemiology of rickettsial disease has not been confirmed. Another concern is dermatitis caused by the bite of these mites, popularly known as trombiculiasis. As it is well known, thrombiculid mites are not specific and several cases of bites in humans have been reported. Thus, the purpose of the present study is to know the current situation of chigger mites parasitizing birds, to clarify aspects of its taxonomic complexity, as well as to provide information about its participation in the epidemiology of Rickettsia in some localities in the southeastern region of the country. From the material examined in the present study were identified 8 species: Blankaartia shatrovi n. sp., Blankaartia sinnamaryi, Microtrombicula n. sp., Eutrombicula tinami, Eutrombicula goeldii, Parasecia n. sp.1, Parasecia n. sp.2, Parasecia n. sp.3. The mites were kept in absolute alcohol, were submitted to DNA extraction and investigation of the presence of Rickettsia. One of the samples showed 100% for Rickettsia felis. Therefore, for Brazil now, we have 13 species described for the entire national territory, with the exception of the Midwest region, and, in addition, the first record of the presence of Rickettsia in chigger mites on South America. / O Brasil possui 58 espécies de ácaros trombiculídeos parasitando diferentes grupos animais. E destas, somente 6 espécies foram reportadas para aves, sendo 1 de Apolonia, 2 de Eutrombicula, 1 de Neoschoengastia e 2 de Parasecia. As larvas de trombiculídeos provocam lesões profundas e reações cutâneas no hospedeiro, sendo por muitas vezes citados como vetores de agentes patogênicos. Nos Estados Unidos, os departamentos de saúde pública se depararam com a necessidade de catalogação e conhecimento da biologia desses ácaros por serem considerados potenciais vetores de Rickettsia spp. No Brasil, os primeiros casos de Febre Maculosa Brasileira (FMB) diagnosticados em São Paulo, foram associados a esses ácaros porque terem sido encontrados em focos da doença. No entanto, o seu papel na epidemiologia da riquetsiose não foi confirmado. Outra preocupação é a dermatite causada pela mordida desses ácaros, popularmente conhecida como trombiculíase. Como é bem conhecido, trombiculídeos não são específicos e vários casos de mordidas em humanos já foram relatados. Dessa forma, a proposta do presente estudo é conhecer a situação atual dos trombiculídeos de aves, esclarecer os aspectos de sua complexidade taxonômica, bem como fornecer informações sobre sua participação na epidemiologia de riquétsias em algumas localidades da região sudeste do país. Do material examinado no presente estudo foram identificadas 8 espécies: Blankaartia shatrovi sp. n., Blankaartia sinnamaryi, Microtrombicula sp. n., Eutrombicula tinami, Eutrombicula goeldii, Parasecia sp. n.1, Parasecia sp. n.2, Parasecia sp. n.3. Os ácaros mantidos em álcool absoluto foram submetidos à extração de DNA e investigação da presença de Rickettsia. Uma das amostras aprentou 100% para Rickettsia felis. Portanto, para o Brazil agora, temos 13 espécies descritas para todo o território nacional, com excessão da região Centro-Oeste, e, além disso, o primeiro registro da presença de Rickettsia em ácaros trombiculídeos da América do Sul.