In 2020, adult hard ticks (males and females) were collected from great horned owls [Bubo virginianus (Gmelin, 1788)] in the coastal region in southern Brazil. The engorged females were allowed to oviposit in the laboratory and hatched larvae could be obtained. Analyses of the external morphology of the adult ticks revealed that they represent a new species, which was named Amblyomma monteiroae n. sp. Partial sequences of the mitochondrial 16S rRNA gene and the nuclear second internal transcribed spacer (ITS2) were generated from a male and a female. Their 16S rRNA haplotypes were identical to each other and closest (96% identity) to corresponding sequences of Amblyomma parvitarsum Neumann, 1901, and 90% identical to Amblyomma neumanni Ribaga, 1902. Their ITS2 haplotypes were 95.8 to 96.0 identical to the single ITS-2 partial sequence of A. parvitarsum available in GenBank. In the phylogenetic trees inferred by both 16S rRNA and ITS2 partial sequences, A. monteiroae n. sp. formed a clade with A. parvitarsum, with A. neumanni branching sister to this clade. Amblyomma monteiroae n. sp. is genetically and morphologically related to A. parvitarsum. Both tick species are unique in combining the following morphological characters: scutum extensively ornate; eyes rounded and bulging; coxa I with two moderate pointed spurs, the external longer than the internal; a single triangular short spur on coxae II-III; presence of two spines on the tibia of legs II-IV; hypostomal dentition 3/3, trochanters without spurs. However, the males of the two species can be separated by specific features in palps and festoons, whereas the females differ in specific features of the coxal spurs. The larva of A. monteiroae n. sp. can be morphologically distinguished from A. parvitarsum only by morphometry, with the former species being slightly smaller. Currently, A. monteiroae n. sp. is restricted to southern Brazil, and the only known host is B. virginianus (Strigiformes: Strigidae). The present study increases the Amblyomma Brazilian fauna to 34 species.

Domestic and wild felids are frequently parasitized by apicomplexan protozoa in the genus Cytauxzoon. Expanding species diversity has recently been described within this genus, with potential implications for epidemiology and pathogenesis. In light of these findings, this study assessed the genetic diversity of Cytauxzoon spp. in wild felids (n = 66) from different eco-regions of Brazil and Argentina. Of the 66 blood samples analyzed, 53 (80.3%) were 18S rRNA gene PCR-positive for Cytauxzoon spp., including 43 jaguars (Panthera onca) and 10 ocelots (Leopardus pardalis). Panthera onca specimens (100%, 43/43) were most frequently infected, followed by Leopardus pardalis (76.9%; 10/13). Cytauxzoon spp. were not detected in Leopardus braccatus (n = 1) or Puma concolor (n = 9). Phylogenetic analyses of fragments of the 18S rRNA, cytB, and cox-1 gene sequences from jaguars were closely related to Cytauxzoon felis. In contrast, sequences from ocelots were more closely associated with Cytauxzoon brasiliensis. Distance and haplotype analysis further confirmed the circulation of at least two distinct genovariants of C. felis among jaguars, as evidenced by their close positioning and low genetic divergence (0–0.14% for 18S rRNA, 0.37–0.56% for cytB, and 0.08–0.74% for cox-1). Additionally, sequence data from ocelots suggested that multiple genovariants of C. brasiliensis are circulating among these cats in different Brazilian eco-regions. Our study provides evidence of two distinct Cytauxzoon organisms parasitizing free-ranging and captive jaguars and ocelots, respectively, in Brazil and Argentina.

Dermatobia hominis is a parasite widely distributed in neotropical regions. The parasitic phase of the cycle is characterized by the formation of a subcutaneous nodule in the host, which can promote infestation by other dipterans and skin infections. The aim of this report is to register parasitism by D. hominis in free-ranging Panthera onca captured in the Brazilian wetland and to determine significant biological and meteorological factors that are likely to influence the presence of larval parasitism in captured wild jaguars. Between 2011 to 2020, 34 jaguars were captured and examined manually by searching for lesions characteristic of myiasis. By manual compression in the subcutaneous nodules, larvae morphologically identified as D. hominis (first and third instars) were collected from 13 jaguars. A multinomial logistic regression showed that adult jaguars had 16.49-fold higher odds of being parasitized than subadults. Thus, jaguars captured in the season of July–September have 34.01- and 11.42-fold higher odds of being parasitized compared to the seasons of October–December and April–June, respectively, which is associated with high total monthly precipitation in the previous season. The present study is the first to describe parasitism by D. hominis larvae in jaguars.

This study aimed to prospectively evaluate the risk factors of infection by Aelurostrongylus abstrusus in Brazilian cats with cough and/or radiographic changes, using as diagnostic tools the Baermann method (BM), polymerase chain reaction (PCR) of feces, bronchoalveolar lavage fluid (BALF), and cytology. Forty-three cats that were presented with cough or lung radiographic abnormalities compatible with bronchoalveolar disease were included in the study. After clinical evaluation, feces samples were collected to investigate lungworm parasitism through BM and PCR. BALF was performed to provide samples for cytology, bacteriology, and fungal culture. Stool PCR was considered the gold standard for diagnosis tests, and the other methods were evaluated by their agreement. PCR presented 74% (32/43) of positivity for A. abstrusus, while in the BM, 41% (18/43) were positive. BM showed sensitivity of 56.25% and specificity of 100% when compared with PCR. No larva was found in the cytological evaluation of 21 BALF samples. Lungworm is an important cause of bronchopulmonary disease in domestic cats in Brazil and should be included as a differential diagnosis when a cat is presented with cough or radiographic abnormalities. BM is a sensitive, non-invasive, and cheap technique to diagnose the disease, but it is not as sensitive as PCR.

The Amazon biome harbors an exceptional diversity of wildlife, yet remains understudied regarding tick-borne pathogens. This study investigated the species richness of ixodid ticks and the occurrence of associated microorganisms in three natural areas of the Brazilian Amazon. During 2023-2024, a total of 1,084 ticks were collected from vegetation and vertebrate hosts and identified into 16 species, predominantly within the genus Amblyomma. A subset of 289 ticks was subjected to molecular screening for bacteria of the genera Rickettsia, Anaplasma, and Borrelia, as well as protozoa of the order Piroplasmida. No DNA of known pathogenic rickettsiae was detected. Instead, Rickettsia amblyommatis was identified in multiple Amblyomma species, while Rickettsia bellii and Rickettsia rhipicephali were detected at lower frequencies. Two isolates of R. amblyommatis were successfully established in Vero cell culture. Additionally, an Anaplasma sp. closely related to strains previously detected in South America, including in humans, and 'Candidatus Allocryptoplasma sp.' were identified in individual ticks. Borrelial DNA was detected in 11 ticks, with sequences clustering within the reptile-associated Borrelia group, including specimens collected from a red-footed tortoise, suggesting a potential reptile reservoir. No piroplasmid DNA was detected. These findings reveal a high richness of tick species and associated microorganisms in the Amazon, dominated by agents of unknown or uncertain pathogenicity. The apparent absence of confirmed pathogenic rickettsiae in preserved forest environments contrasts with other Brazilian regions and reinforces the need for continued epidemiological surveillance. Overall, this study provides baseline data and highlights the Amazon as a potential reservoir of neglected and emerging tick-borne agents.