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Background: South American birds are known to play a significant role in life cycles of various hard ticks, particularly within Amblyomma genus. However, the tick fauna from the Amazon region has been poorly studied, being limited to very few studies. Objective: To report tick infestations on wild birds captured in a region of the Amazon forest, Acre state, Brazil, and to evaluate rickettsial infection in these ticks. Methods: Wild birds were captured by mist-nets and examined for the presence of ticks, which were all collected and identified to species level by taxonomic keys and/or molecular methods. In addition, part of these ticks was individually tested by PCR targeting portions of three rickettsial genes (gltA, ompA, ompB). Results: Among 1,322 captured birds, 79 individuals (6.0%) were infested by one of the following ticks species: Amblyomma nodosum Neumann, 1899 (72 nymphs), Amblyomma longirostre (Koch, 1844; seven larvae, 13 nymphs), Amblyomma humerale Koch 1844 (four nymphs), Amblyomma geayi Neumann, 1899 (two larvae, two nymphs), and 421 larvae of Amblyomma spp Rickettsia sp strain NOD was detected in 3/26 A. nodosum, and Rickettsia amblyommatis in 5/8 A. longirostre and 1/2 A. geayi ticks tested. Conclusion: This is the first study about ticks parasitizing wild birds in Acre state, adding new host-parasite relationships, new tick species records (A. humerale and A. nodosum) and two rickettsial agents (R amblyommatis and Rickettsia sp strain NOD) for the first time in Acre.

The abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors) presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous) developed during long co-evolving processes. Ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. They are obligatory hematophagous ectoparasites and responsible as vectors or reservoirs at the transmission of pathogenic fungi, protozoa, viruses, rickettsia and others bacteria during their feeding process on the hosts. Ticks constitute the second vector group that transmit the major number of pathogens to humans and play a role primary for animals in the process of diseases transmission. Many studies on bioecology of ticks, considering the information related to their population dynamics, to the host and the environment, comes possible the application and efficiency of tick control measures in the prevention programs of vector-borne diseases. In this review were considered some taxonomic, morphological, epidemiological and clinical fundamental aspects related to the tick-borne infections that affect human and animal populations.

Background Rickettsia parkeri strain Atlantic rainforest has emerged in Brazil during the last 10 years, with three laboratory-confirmed human cases. While these cases were epidemiologically associated with the tick Amblyomma ovale , in none of them the tick specimens that bit the patients could be identified. Results We report a clinical case of spotted fever rickettsiosis that was acquired in an Atlantic forest area in Bahia state, northeast Brazil. The case was determined to be caused by R. parkeri strain Atlantic rainforest, based on molecular analysis of the crust removed from the tick bite site (inoculation eschar) of the patients’ skin. DNA extracted from the crust yielded partial sequences of three rickettsial genes ( gltA , ompA and ompB ), which were 99–100% identical to R. parkeri strain Atlantic rainforest. The tick specimen that was attached to patient skin was identified as a female of A. ovale. Conclusions We report the fourth confirmed case of spotted fever rickettsiosis caused by R. parkeri strain Atlantic rainforest, providing to our knowledge for the first time, direct evidence of R. parkeri strain Atlantic rainforest transmission by A. ovale .

We describe New World screwworm (Cochliomyia hominivorax) infestation in 2 injured mountain tapirs (Tapirus pinchaque) from a protected area in the Central Andes, Colombia. Screwworms were not a known threat to mountain tapirs. Community outreach is needed to raise awareness on effects of this parasite on humans, domestic animals, and wildlife.

Ticks are obligate ectoparasite arthropods of the class Arachnida distributed worldwide and can parasitize many animals. They constitute one of the most important groups of vectors of infectious diseases, including zoonoses. The objective of this study was to report the parasitism by Amblyomma ovale Koch, 1844 in a domestic dog (Canis lupus familiaris Linnaeus, 1758) in Santa Maria, in the central region of the state of Rio Grande do Sul, Brazil. Two specimens of ectoparasites found on a domestic dog, living in a rural property, were sent to the Laboratory of Veterinary Parasitology at the Federal University of Santa Maria for taxonomic identification. The two specimens found were classified as adult male and female of A. ovale. Through this study, the parasitism of this species is reported for the first time in the central region of the state of Rio Grande do Sul, Brazil, in a domestic dog, allowing the infestation and transmission of diseases to humans.

Introduction: Since the first reports of coronavirus disease 2019 (COVID-19) in December 2019, the disease has spread worldwide. Different social isolation strategies have been adopted to reduce community transmission, but few studies have evaluated the pattern of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection in a family cluster during periods of isolation. We report an outbreak in 24 members of a family cluster during a period of social distancing. Methodology: We carried out an observational descriptive study of a family cluster infected with SARS-CoV-2 in Pernambuco, Northeast Brazil. Laboratory confirmation included RT-PCR of nasopharyngeal samples or IgM or IgG serology. Results: The attack rates were 75% (19/24) based on laboratory-confirmed cases and 87.5% (21/24) including probable cases. The time of spread was 17 days from the first case. All patients had mild symptoms, requiring no hospitalization, and none of them died. The frequency of symptomatic, laboratory-confirmed patients was higher among adults (94%) than among children (50%); the paediatric age group also had a higher frequency of exposed individuals who remained negative for infection. Ground-glass opacities on chest computed tomography were present in all patients with reported dyspnoea. Conclusion: This study highlights a high risk of intrahousehold transmission from an index case, suggesting the need for (I) specific guidelines during periods of social distancing, (II) minimization of external exposures and, above all, (III) adoption of strict quarantine measures for suspected cases and family members to prevent outbreaks from spreading.

Background In Brazil, spotted fever (SF) is caused by the bacteria Rickettsia parkeri and Rickettsia rickettsii . Seroepidemiological data on Rickettsia spp. in humans are rare in Brazil and nonexistent in the Amazon biome. We sought to quantify antibodies reactive to Rickettsia spp. in serum samples collected from humans in the Amazonia biome, and to detect Rickettsia spp. in ticks parasitizing these hosts. Methods Human blood samples were collected from three different locations within the eastern Amazon in Maranhão State, northeastern Brazil between 2010 and 2018. Sera generated from those samples were tested for the presence of antibodies reactive to Rickettsia by immunofluorescence assay (IFA) using crude antigens from five Rickettsia isolates from Brazil: R. rickettsii strain Taiaçu, R. amblyommatis strain Ac37, Rickettsia rhipicephali strain HJ5, R. parkeri strain At24, and Rickettsia bellii strain Mogi. Between 2020 and 2025, ticks were manually collected while attached to the skin of humans in seven municipalities in Maranhão State. Adult ticks were randomly selected and individually processed for DNA extraction and examined using a real-time PCR (qPCR) assay targeting a fragment of the rickettsial gltA gene. The qPCR-positive samples were subsequently examined by conventional PCR (cPCR) targeting the ompA gene of SFG rickettsiae. The cPCR amplicons were purified and sequenced bidirectionally using the amplification primers. The resulting sequences were compared with those in GenBank using BLASTn to identify related Rickettsia spp. Results A total of 341 human serum samples were analyzed, and 145 (42.5%) were recorded as reactive with at least one species of Rickettsia . Among the reactive samples, 68 (47%) were from Imperatriz, 45 (31%) from Açailândia, and 32 (22%) from the municipality of São Luís. Rickettsia rhipicephali was recorded as the possible antigen involved in a homologous reaction (PAIHR) in one individual, R. amblyommatis in five, and R. bellii in three. A total of 187 ticks were collected parasitizing humans in the Amazon biome. Molecular analyses revealed that Rickettsia DNA was present in 44.4% (4/9) of A. cajennense s.s. from Açailândia, 52.4% (22/42) from Centro Novo do Maranhão, and 0% (0/8) from Imperatriz. Among the adults of A. coelebs from Centro Novo do Maranhão, 36.8% (7/19) tested positive. In contrast, all adults of A. oblongoguttatum from the same location tested negative (0/20). Conclusions This is the first study to detect anti- Rickettsia antibodies in humans and to identify R. amblyommatis in ticks parasitizing humans in the Amazon biome. The detection of R. amblyommatis in human-biting ticks, together with concurrent seropositivity in human sera from the same region, supports the hypothesis that this agent is actively circulating in the Amazon biome and may be responsible for undiagnosed cases of nonlethal spotted fever in the area. Graphical abstract

Background The tick Amblyomma cajennense sensu stricto ( A. cajennense s.s.) frequently parasitizes animals and humans in the Amazon biome, in addition to being a vector of Rickettsia amblyommatis . In the present study, we evaluated both the population dynamics of A. cajennense s.s. in a degraded area of the Amazon biome and the presence of rickettsial organisms in this tick population. Methods The study was carried out in a rural area of the Santa Inês municipality (altitude: 24 m a.s.l.), Maranhão state, Brazil. Ticks were collected from the environment for 24 consecutive months, from June 2021 to May 2023. The region is characterized by two warm seasons: a rainy season (November–May) and a dry season (June–October). We characterized the temporal activity of A. cajennense s.s. on the vegetation by examining questing activity for each life stage (larvae, nymphs, adults [males and females]) in relation to the dry and rainy season. Ticks collected in this study were randomly selected and individually tested by a TaqMan real-time PCR assay that targeted a 147-bp fragment of the rickettsial gltA gene. Results Overall, 1843 (62.4%) adults (52.6% females, 47.4% males), 1110 (37.6%) nymphs and 398 larval clusters were collected. All adult females and nymphs were morphologically identified as A. cajennense s.s. Larval activity was observed from April to December, with a peak from June to September (dry season); nymph abundance peaked from September to November (transition period between dry and rainy seasons); and adult ticks were abundant from October to May (spring/summer/early autumn). The infection rate by R. amblyommatis in A. cajennense s.s. ticks was at least 7% (7/99). Conclusion Our data suggest a 1-year generation pattern for A. cajennense s.s., with a well-defined seasonality of larvae, nymphs and adults in the Amazon biome. Larvae predominate during the dry season, nymphs are most abundant in the dry-rainy season transition and adults are most abundant in the rainy season. The presence of R. amblyommatis in adult ticks suggests that animals and humans in the study region are at risk of infection by this species belonging to the spotted fever group of Rickettsia . Graphical Abstract

The Cerrado Biome is the second largest in Brazil covering roughly 2 million km2, with varying features throughout its area. The Biome is endangered but it is also source of animal species for rural, green urban and degraded rainforest areas. Ticks are among Cerrado species that establish at anthropogenic sites and although information about them is steadily increasing, several features are unknown. We herein report tick species, abundance and some ecological relationships within natural areas of the Cerrado at higher altitudes (800–1500 m) within and around Serra da Canastra National Park, in Minas Gerais State Brazil. In total of 1196 ticks were collected in the environment along 10 campaigns held in 3 years (2007–2009). Amblyomma sculptum was the most numerous species followed by Amblyomma dubitatum and Amblyomma brasiliense. Distribution of these species was very uneven and an established population of A. brasiliense in the Cerrado is reported for the first time. Other tick species (Amblyomma ovale, Amblyomma nodosum, Amblyomma parvum, Ixodes schulzei and Haemaphysalis leporispalustris) were found in lesser numbers. Domestic animals displayed tick infestations of both rural and urban origin as well as from natural areas (Rhipicephalus sanguineus sensu lato, Rhipicephalus microplus, Dermacentor nitens, A. sculptum, A. ovale, Amblyomma tigrinum, Argas miniatus). Amblyomma sculptum had the widest domestic host spectrum among all tick species. DNA of only one Rickettsia species, R. bellii, was found in an A. dubitatum tick. Several biological and ecological features of ticks of the studied areas are discussed.

Amphibians and Squamata reptiles belonging to a zoological collection were screened for ectoparasites, which were removed from the hosts and identified using morphological keys. Descriptive statistics and analysis of the association between the parasite and host characteristics (taxonomic group, capture location and habitat) were done. Among the 1256 animals examined (319 amphibians and 937 reptiles), 86 individuals were parasitized, corresponding to a frequency of 6.9% (6.6% reptiles and 7.5% amphibians). Ticks in the adult and nymph stages were identified to the species level; all of them belonged to the species Amblyomma dissimile. The larvae were identified to the genus level and were all Amblyomma sp. In total 69 larvae, 28 nymphs and eight adults were found. The most parasitized species was the frog Rhinella major: 24 parasitized animals of 65 examined (36.9%). There was a difference (P < 0.001) between parasitism by ticks of the genus Amblyomma with regard to the habitat of capture of the parasitized animal, with a higher parasitism rate in hosts that inhabited open areas as compared to animals ensconced in forest areas and edges of forests. New tick-host associations are given.