Molecular detection of Rickettsia species in ticks collected in the Mexico-USA transboundary region.

Zoonotic tick-borne diseases, including those caused by Rickettsia species, continue to have serious consequences for public health worldwide. One such disease that has emerged as a major problem in several countries of the American continent is the Rocky Mountain Spotted Fever (RMSF) caused by the bacterium Rickettsia rickettsii. Several tick species are capable of transmitting R. rickettsia, including Amblyomma cajennense, A. aureolatum, A. imitator, Rhipicephalus sanguineus, Dermacentor andersoni, D. variabilis and possibly A. americanum. Despite previous reports in Mexico linking new outbreaks of RMSF to the presence of these tick species, no robust measures have tackled transmission. In the present study, we amplified R. rickettsii from 109 test DNA samples extracted from ticks collected from several animals and humans of Tamaulipas, Mexico, between November 2015 and December 2017. Our analysis revealed the presence of R. rickettsii in six samples and these findings contribute to a spatial distribution map that is intended to minimize the risk of transmission to humans.

Detection of border disease virus in Mexican cattle.

The genus Pestivirus within Flaviviridae is comprised of four recognized species, namely, bovine viral diarrhoea virus 1 (BVDV-1), bovine viral diarrhoea virus 2 (BVDV-2), border disease virus (BDV) and classical swine fever virus (CSFV). BDV, while primarily infecting sheep and goats, has also been reported in cattle and wild animals. Infections of sheep and goats result in economic loss due to abortions and the birth of persistently infected animals that have poor production and reduced life expectancy. In this study, we report the detection of BDV in cattle serum collected as part of pestivirus surveillance programme from six regions of Mexico, where a 67.1% of BVDV seroprevalence was calculated previously. Phylogenetic analyses based on comparison of the 5'UTR region typed the Mexican strains as BDV-1. Border disease (BD) is listed as an exotic disease in Mexico, and the origin of BDV found in these cattle is unclear. This is the first identification of BDV in Mexican cattle.

Decrease in the cattle tick Rhipicephalus microplus biological parameters using anti-subolesin peptide antibodies by artificial capillary feeding.

Ticks represent a threat to animal health worldwide and are considered the second most important vectors of human diseases. The main method of control of ticks has been the usage of chemical products; however, the use of acaricides has resulted in some serious drawbacks such as acaricide-resistant ticks and environmental pollution. As a result the use of immunological control using tick proteins is suggested as an alternative to control tick populations. The protocols used to test the ticks to antigens, needs a complementary method that would allow control to be carried out in external conditions. In this context, the use of the in vitro capillary feeding represents a low cost alternative to test candidate antigens allowing to get important data on the protective effect during interactions between antigenantibody. In order to evaluate the effect in biological parameters of female R. microplus ticks by artificial feeding with bovine blood containing anti-subolesin peptide IgG's obtained at different times after immunization. Results of this study showed the effect on weight of ticks and oviposition due to antibodies obtained at weeks 3, 5 and 7 after immunization. The results proved that anti-subolesin peptide IgG´s at week 7 demonstrated better effect reducing tick weight by 45% and oviposition by 71% (P<0.05) with respect to tick fed on blood with preimmune serum. These results strongly suggested that the negative effects in cattle tick biological parameters were the result of the protective antibodies against subolesin peptide. Finally, the artificial feeding of ticks should be used to evaluate antigen-specific antibodies avoiding external factors.