Comparative Proteomics of Coxiella like Endosymbionts (CLEs) in the Symbiotic Organs of Rhipicephalus sanguineus Ticks

Here we compare the Coxiella -like endosymbionts (CLE) proteomes from Malpighian tubule (Mt) and the ovaries (Ov) of the brown dog tick Rhipicephalus sanguineus . Our results support the hypothesis that CLEs function interdependently with host requirements in each of the organs.

Ticks and Tick-Borne Pathogens in Domestic Animals, Wild Pigs, and Off-Host Environmental Sampling in Guam, USA

Background: Guam, a United States of America (USA) island territory in the Pacific Ocean, is known to have large populations of ticks; however, it is unclear what the risk is to wildlife and humans living on the island. Dog (Canis familiaris), cat (Felis catus), and wild pig (Sus scrofa) sentinels were examined for ticks, and environmental sampling was conducted to determine the ticks present in Guam and the prevalence of tick-borne pathogens in hosts.Methods and Results: From March 2019-November 2020, ticks were collected from environmental sampling, dogs, cats, and wild pigs. Blood samples were also taken from a subset of animals. A total of 99 ticks were collected from 27 environmental samples and all were Rhipicephalus sanguineus, the brown dog tick. Most ticks were collected during the dry season with an overall sampling success rate of 63% (95% CI: 42.4–80.6). 6,614 dogs were examined, and 12.6% (95% CI: 11.8–13.4) were infested with at least one tick. One thousand one hundred twelve cats were examined, and six (0.54%; 95% CI: 0.20–1.1) were found with ticks. Sixty-four wild pigs were examined and 17.2% (95% CI: 9.5–27.8) had ticks. In total, 1,956 ticks were collected and 97.4% of ticks were R. sanguineus. A subset of R. sanguineus were determined to be the tropical lineage. The other tick species found were Rhipicephalus microplus (0.77%), Amblyomma breviscutatum (0.77 %), and a Haemaphysalis sp. (0.51%). Blood samples from 136 dogs, four cats, and 64 wild pigs were tested using polymerase chain reaction (PCR) and DNA sequencing methods. Five different tick-borne pathogens with the following prevalences were found in dogs: Anaplasma phagocytophilum 5.9% (95% CI: 2.6–11.3); Anaplasma platys 19.1% (95% CI: 12.9–26.7); Babesia canis vogeli 8.8% (95% CI: 4.6–14.9); Ehrlichia canis 12.5% (95% CI: 7.5–19.3); Hepatozoon canis 14.7% (95% CI: 9.2–28.8). E. canis was detected in one cat, and no tick-borne pathogens were detected in wild pigs. Overall, 43.4% (95% CI: 34.9–52.1) of dogs had at least one tick-borne pathogen. Serological testing for antibodies against Ehrlichia spp. and Anaplasma spp. showed prevalences of 14.7% (95% CI: 9.2–28.8) and 31.6% (95% CI: 23.9–40), respectively.Conclusion: Four different tick species were found in Guam to include a Haemaphysalis sp., which is a previously unreported genus for Guam. Dogs with ticks have a high prevalence of tick-borne pathogens which makes them useful sentinels.

Acaricide activity of Piper macedoi Yunck essential oil against Rhipicephalus sanguineus

This study evaluated the acaricide efficacy of Piper macedoi essential oil on larvae of ticks of the species Rhipicephalus sanguineus. The essential oil was extracted by hydrodistillation in a Clevenger-type apparatus. The test consisted of six treatments: from the group I to IV, samples corresponded to different concentrations of essential oil (500 μg.mL-1; 250 μg.mL-1; 100 μg.mL-1 and 50 μg.mL-1) diluted in Tween 80 at 2%. Groups V and VI corresponded to the negative controls (with distilled water and Tween 80 to 2%) and the positive control (with acaricide Amitraz at 12.5%), respectively. The essential oil was rich in apiole (39.81%) and dillapiole (26.47%). The essential oil of P. macedoi presented an activity against the larvae of R. sanguineus, with a better efficiency observed for concentrating 500 μg.mL-1, mortality of 80.67%, indicating a dose-dependent response.

Scenes From Tick Physiology: Proteins of Sialome Talk About Their Biological Processes

Ticks are blood-sucking parasites with different strategies of feeding depending on the tick family. The major families are Ixodidae or Argasidae, being slow or fast feeders, respectively. In the recent years, the advances in molecular sequencing techniques have enabled to gain knowledge about the proteome of the tick’s salivary glands. But an holistic view of the biological processes underlying the expression of the sialome has been neglected. In this study we propose the use of standard biological processes as a tool to draw the physiology of the tick’s salivary glands. We used published data on the sialome of Rhipicephalus sanguineus s.l. (Ixodidae) and Ornithodoros rostratus (Argasidae). A partial set of proteins obtained by these studies were used to define the biological process(es) in which proteins are involved. We used a directed network construction in which the nodes are proteins (source) and biological processes (target), separately for the low-level processes (“children”) and the top-level ones (“parents”). We applied the method to feeding R. sanguineus at different time slices, and to different organs of O. rostratus. The network connects the proteins and the processes with a strength directly proportional to the transcript per millions of each protein. We used PageRank as a measure of the importance of each biological process. As suggested in previous studies, the sialome of unfed R. sanguineus express about 30% less biological processes than feeding ticks. Another decrease (25%) is noticed at the middle of the feeding and before detachment. However, top-level processes are deeply affected only at the onset of feeding, demonstrating a redundancy in the feeding. When ixodid-argasid are compared, large differences were observed: they do not share 91% of proteins, but share 90% of the biological processes. However, caution must be observed when examining these results. The hypothesis of different proteins linked to similar biological process(es) in both ticks is an extreme not confirmed in this study. Considering the limitations of this study, carried out with a selected set of proteins, we propose the networks of proteins of sialome linked to their biological processes as a tool aimed to explain the biological processes behind families of proteins.

on Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

A study was undertaken on the ovicidal and larval repellent activity of Tagetes erecta leaf and flower extracts on Rhipicephalus sanguineus (Latreille, 1806), an important tick species in the world from an economic and medical point of view. Ethanol and methanol extracted plant products tested against the eggs and larvae of R. sanguineus indicated that the ethanol extract of flower had maximum ovicidal activity (86.1%), followed by the ethanol extract of leaf (75%) at 25 mg ml-1 concentration. In all analyses, the homogeneity of variance was significant. The probit analysis clearly indicated that the ethanol extract of the flower has a higher ability to kill the eggs. In the case of larval repellency tested, both extracts of leaf showed the highest repellency (83%) at 2.5 mg ml-1. Significant tick repellency (> 90%) was found in both methanol and ethanol extracts of flower at 2.5 mg ml-1. GC-MS analysis of extracts revealed the presence of bioactive insecticidal compounds such as yangambin, cyclohexane and neophytadine.

One Health Approach to Rickettsiosis: A Five-Year Study on Spotted Fever Group Rickettsiae in Ticks Collected from Humans, Animals and Environment

The spotted fever group of Rickettsiae is a heterogeneous group of Rickettsiae transmitted by ticks, causing similar diseases in humans (spotted fever). Until recently, it was supposed that a single pathogenic tick-borne SFG Rickettsia circulated in each different geographic area and that R. conorii subsp. conorii was the SFG Rickettsiae circulating in Italy, but in the last decade, thanks to molecular diagnostic, several different Rickettsia species, previously not considered pathogenic for decades, have been isolated from ticks and definitively associated to human disease, also in Italy. The present survey was carried out with the aim of investigating the presence of different SFG Rickettsia species in a geographic area where no information was available. Ticks collected from animals submitted to necropsy, removed from humans in local hospitals and collected from the environment were identified and tested by PCR for Rickettsia spp. based on the gltA gene, and positive PCR products were sequenced. A total of 3286 ticks were collected. Fifteen tick species were recognized, the most represented (79.52%) species in the collection was Ixodes ricinus, followed by Rhipicephalus sanguineus (9.13%). The overall prevalence of Rickettsia infection was 7.58%. Eight species of Rickettsia were identified, the most frequent was R. monacensis (56%), followed by R. helvetica (25.50%). Noteworthy, is the detection in the present study of Rrhipicephali, detected only twice in Italy. These are the first data available on SFG Rickettsiae circulation in the study area and they can be considered as starting point to assess the possible risk for humans.

Molecular Detection of Zoonotic and Non-Zoonotic Pathogens from Wild Boars and Their Ticks in the Corsican Wetlands

Corsica is the main French island in the Mediterranean Sea and has high levels of human and animal population movement. Among the local animal species, the wild boar is highly prevalent in the Corsican landscape and in the island’s traditions. Wild boars are the most commonly hunted animals on this island, and can be responsible for the transmission and circulation of pathogens and their vectors. In this study, wild boar samples and ticks were collected in 17 municipalities near wetlands on the Corsican coast. A total of 158 hunted wild boars were sampled (523 samples). Of these samples, 113 were ticks: 96.4% were Dermacentor marginatus, and the remainder were Hyalomma marginatum, Hyalomma scupense and Rhipicephalus sanguineus s.l. Of the wild boar samples, only three blood samples were found to be positive for Babesia spp. Of the tick samples, 90 were found to be positive for tick-borne pathogens (rickettsial species). These results confirm the importance of the wild boar as a host for ticks carrying diseases such as rickettsiosis near wetlands and recreational sites. Our findings also show that the wild boar is a potential carrier of babesiosis in Corsica, a pathogen detected for the first time in wild boars on the island.

RANGELIOSE CANINA

A Rangeliose canina é uma doença que acomete canídeos domésticos e selvagens que foi descrita pela primeira vez no início do século XX. Popularmente chamado de “Nambyuvú” (Palavra Guarani que significa “orelha que sangra”, sendo este um dos sinais em animais acometidos pela doença), é causada pelo piroplasma Rangelia vitalii, pertencente ao Filo Apicomplexa, à Ordem Piroplasmorida e está geneticamente relacionado aos hemoprotozoários da Família Babesidae. Este protozoário se caracteriza por infectar hemácias, leucócitos e células do endotélio vascular e se apresenta tipicamente como um distúrbio hemolítico. Apesar de possuir um tratamento eficaz, existe a necessidade de prevenção para que os animais não se infectem com este hemoparasita, o que é um pouco difícil pois o fator climático brasileiro fornece as condições ideais para o desenvolvimento dos vetores biológicos desses parasitas, que são os carrapatos Amblyomma aureolatum e Rhipicephalus sanguineus. O objetivo deste trabalho é facilitar o entendimento sobre essa doença que é muito importante do ponto de vista clínico e reunir informações a respeito dessa patologia de forma clara e sucinta, uma vez que ela esteve em esquecimento acadêmico por anos e ainda hoje é confundida com outras hemoparasitoses.