Confirmation of the presence of Rickettsia felis infecting Ornithodoros puertoricensis in Mexico.

Soft ticks are neglected competent vectors of a wide range of pathogenic microorganisms, among which bacteria of the genera Rickettsia and Borrelia stand out. In Mexico, previous studies have shown the presence of a member of the Ornithodoros talaje complex in the Virginia opossum (Didelphis virginiana Didelphimorphia: Didelphidae Kerr) from southeastern Mexico. However, its specific identification has not been achieved. Two D. virginiana were treated in a private clinic during the period of April-May 2022. Tick larvae were manually removed, DNA extraction was performed, and some genes from various bacterial and parasitic pathogens were amplified and sequenced. A total of 96 larvae were recovered, which were morphologically identified as Ornithodoros puertoricensis (Ixodida: Argasidae Fox); the 16 S sequences showed a similarity of 96.79%-99.51% with sequences of O. puertoricensis from Panama and Colombia. The presence of Rickettsia felis (Rickettsiales: Rickettsiaceae Bouyer et al.) was detected in 15 specimens from one host. The soft tick O. puertoricensis is recorded for the first time as an ectoparasite of the Virginia opossum in America and represents the second report for this soft tick in Mexico since 1963. This represents the most northern record of this tick species in its geographic distribution and brings a new soft tick-Rickettsia association.

Efficacy of hydroethanolic extract of Randia aculeata seed against the southern cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) on naturally infested cattle under field conditions.

The cattle tick Rhipicephalus (Boophilus) microplus is a major problem of concern for cattle industry in tropical and subtropical areas. Control of cattle tick is based mainly on the use of chemical acaricides, which has contributed to the emerging problem of selection of resistant tick lineages. Plants have been used as an alternative to conventional acaricidal drugs. On the other hand, the acaricidal activity of hydroethanolic extract of Randia aculeata seed (EHRA) has been demonstrated against R. microplus under laboratory conditions. However, the utility of EHRA seed as a potential acaricidal needs to be determined under field conditions. For this reason, the aim of this study was to evaluate the efficacy of the EHRA against R. microplus sprayed on naturally infested calves, determine the effect of the EHRA seed on acetylcholinesterase activity in R. microplus larval and identify the chemical composition of EHRA. Forty-five male calves were divided in three groups and treated with: G1 water; G2 EHRA 20% w/v and G3 coumaphos 0.2% v/v. Acetylcholinesterase (AChE) activity in R. microplus larvae was determined by a colorimetric assay. The chemical composition of EHRA was accessed through HPLC/MS. Significantly fewer ticks were observed after 24 h on the treated group compared to control group. EHRA significantly inhibited in vitro AChE activity in R. microplus at all tested concentrations. Chlorogenic acid, vanillinic acid, p-coumaric acid, caffeic acid. rutin, quercetin, (-)-epicatechin, 4-hydroxybenzoic acid, quercetin, vanillin, 2,4-dimethoxy-6-methylbenzoic acid, scopoletin and ferulic acid were identified in the extract. The results provided new data for the elucidation of the mechanisms of EHRA acaricide action and to further evaluate the use as a new alternative control agent against R. microplus under in vivo conditions.

Molecular detection of Theileria cervi in equids from México.

Equine piroplasmosis is a parasitic illness caused by various protozoa of the Babesia and Theileria genera, which parasitize within red blood cells. The transmission of these pathogens occurs through certain genus of ticks, including Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. In recent times, an increase in the identification of new Theileria species and genotypes has been observed. This is further complicated by the presence of mixed Theileria infections in both mammals and tick vectors, particularly in regions where wildlife and livestock share habitats and vectors. Therefore, the objective of this study is to document the occurrence of Theileria cervi in a non-typical host. A total of 88 horses (Equus caballus) and 10 donkeys (Equus asinus) were sampled in three municipalities in Veracruz, Mexico. Molecular techniques were employed to identify Babesia/Theileria through the amplification of a segment of the 18S-rDNA and hsp70 genes. The phylogenetic reconstruction grouped the obtained sequences into a monophyletic cluster alongside sequences of T. cervi. This work represents the first documented occurrence of T. cervi in equids. These findings have significant implications from an epidemiological point of view. In addition, further studies are needed to determine the distribution and pathogenicity of this species for domestic animals and to develop effective control strategies.

Identification of the G184C, C190A and T2134A mutations in the para-sodium channel gene of the southern cattle tick Rhipicephalus (Boophilus) microplus associated with resistance to cypermethrin in northern Veracruz, Mexico.

The southern cattle tick (Rhipicephalus microplus) represents one of the ectoparasites with the greatest distribution worldwide. Infestations by this arthropod can cause a decrease in the production of meat and milk, as well as anaemia and the transmission of bacterial and parasitic agents. For this reason, several active molecules have been developed to control these arthropods. A widely used group of ixodicides are pyrethroids, especially cypermethrin, which have knockdown effects on ticks. Resistance to cypermethrin has been reported in ticks since the 2000s; it was registered for the first time in Mexico in 2009. Even though multiple studies have evaluated resistance with conventional tests, there are few studies in Mexico that have identified the presence of single nucleotide polymorphisms (SNPs) associated with resistance. Hence, the aim of this work was to monitor three mutations associated with resistance in the sodium/chlorine channel in eight populations of ticks from northern Veracruz. Engorged adult females were collected from which genomic DNA was extracted. Subsequently, three mutations in domains II and III of para­sodium channel gene were detected by conventional PCR and sequencing. Global alignments were done with the reference sequences deposited in GenBank. A total of 116 engorged females were analysed, of which 10 tested positive for G184C and C190A of domain II of the para­sodium channel gene. T2134A was present in domain III in a single production unit. This is the first work where molecular monitoring of cypermethrin resistance has been carried out in the northern zone of the state of Veracruz.

New records, and molecular detection of vector-borne pathogens in Felicola subrostratus from eastern Mexico.

The study of lice associated with domestic cats is a neglected area of veterinary parasitology. In particular, the presence of the cat louse Felicola subrostratus, a small Ischnoceran species found in the fur of the domestic cat, is rarely recognized. In America, this species has been reported across six countries. Although it was also recently reported in Mexico, no studies on the molecular identification of the specimens or the monitoring of potential bacterial, and protozoan pathogens have been carried out. Thus, this work aimed to collect, and identify lice associated with domestic and free ranging cats from the states of Veracruz and Tabasco, using amplification and sequencing of the mitochondrial cytochrome c oxidase subunit I (COI), and the ribosomal 18S rDNA genes, and to monitor selected vector-borne bacterial (Bartonella, Mycoplasma, and Rickettsia) and protozoan (Babesia, and Hepatozoon) agents. Only entire lice were used for molecular host and pathogen identification. Eighty-one lice, identified as F. subrostratus, were recovered from five infested cats, and 30 were selected for molecular identification and pathogen surveillance. Analysis of the COI and 18S rDNA partial sequences showed a similarity of 96.79%-100% with sequences of F. subrostratus from the US. Mycoplasma haemofelis and Hepatozoon canis DNA was detected in three and four samples, respectively. This work provides new collection locations for F. subrostratus, and the first sequences of the COI and 18S rDNA genes from Mexico. It also reports two pathogenic microorganisms found in the lice.

First report of Babesia bigemina in Lama glama in a zoological garden of Veracruz, Mexico.

Zoological gardens represent specialised centres for the preservation of biological inventories and genetic diversity, allowing the recognition of multiple species in critical conservation categories. However, the close coexistence of multiple species of vertebrates that may be associated with various species of ectoparasites may be the cause of the transmission of multiple infectious agents, among which tick-borne pathogens stand out. In these areas, several animal species usually live in a small space and proximity to other wildlife, visitors and keepers. In Mexico, little is known about the disease agents transmitted by arthropods in zoological gardens. For this reason, the aim of this study was to identify the presence of Babesia/Theileria in animals maintained in captivity. As a part of a project identifying vector-borne pathogens in wildlife, 24 animals were sampled in the Miguel Angel de Quevedo zoo. Molecular identification of Babesia/Theileria was realised through amplification of a fragment of the mitochondrial cytB gene and the ribosomal 18S-rDNA. Two neotropical camelids (Lama glama) tested positive (2/3 = 66.6%) to Babesia bigemina. Our results represent the first record of B. bigemina in animals in captivity in a zoological garden in Mexico and the first finding of this haemoparasite in neotropical camelids in Mexico.

No molecular evidence of SARS-CoV-2 infection in companion animals from Veracruz, Mexico.

Active epidemiological surveillance of infectious agents represents a fundamental tool for understanding the transmission dynamics of pathogens and establishing public policies that can reduce or limit their expansion. Epidemiological surveillance of emerging agents, such as the recently recognized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of COVID-19, is essential to establish the risk of transmission between species. Recent studies reveal that companion animals are organisms susceptible to being infected by this pathogen due to the close contact they have with their owners. For this reason, the aim of the present work was to detect the presence of SARS-CoV-2 in dogs and cats in the state of Veracruz, Mexico, where there is active transmission of this microorganism in human populations. Oral and nasopharyngeal swab samples were collected from dogs and cats with a history of exposure to patients with COVID-19. Total RNA was extracted and detection of viral genes N1 and N2 was performed by reverse transcription polymerase chain reaction (RT-qPCR). All 130 samples of companion animals tested by RT-qPCR for SARS-CoV-2 were negative at the time they were collected. This study represents the second active surveillance of SARS-CoV-2 in populations of domestic dogs and cats in Latin America and the first approach in Mexico. Given that coronaviruses have shown a high capacity to be transmitted between species, it is imperative to establish measures to prevent this agent from entering and establishing in populations of companion animals.