Rickettsia typhi is an intracellular bacteria who causes murine typhus. His importance is reflected in the high frequency founding specific antibodies against R. typhi in several worldwide seroepidemiological studies, the seroprevalence ranging between 3-36%. Natural reservoirs of Rickettsia typhi are rats (some species belonging the Rattus Genus) and fleas (Xenopsylla cheopis) are his vector. This infection is associated with overcrowding, pollution and poor hygiene. Typically presents fever, headache, rash on trunk and extremities, in some cases may occur organ-specific complications, affecting liver, kidney, lung or brain. Initially the disease is very similar to other diseases, is very common to confuse the murine typhus with Dengue fever, therefore, ignorance of the disease is a factor related to complications or non-specific treatments for the resolution of this infection. This paper presents the most relevant information to consider about the rickettsiosis caused by Rickettsia typhi.

Direct evidence of Rickettsia typhi infection in Rhipicephalus sanguineus ticks and their canine hosts

: Rocky Mountain spotted fever (RMSF) is an ongoing public health crisis in Mexico, particularly in states bordering the United States. The national highest incidence and mortality of RMSF occur in this region, resulting in a case-fatality rate that ranges annually between 10% and 50%, primarily affecting vulnerable groups such as children, elderly adults, and persons living in poverty. Multiple biological, environmental, and social determinants can explain its growing presence throughout the country and how it challenges the health system and society. It is necessary to integrate resources and capacities from health authorities, research centers, and society to succeed in dealing with this problem. Through a scientific symposium, a group of academicians, U.S. health officials, and Mexican health authorities met on November 8–10, 2023, in Hermosillo, Mexico, to discuss the current situation of RMSF across the country and the challenges associated with its occurrence. An urgent call for action to improve national capacity against RMSF in the aspects of epidemiological and acarological surveillance, diagnosis, medical care, case and outbreak prevention, health promotion, and research was urged by the experts. The One Health approach is a proven multidisciplinary strategy to integrate policies and interventions to mitigate and prevent the burden of cases, deaths, and suffering caused by RMSF in Mexico.

Rickettsia are intracellular vector-borne bacteria, which are the etiologic agent of severe infections that could inflict death to their host. The intracellular behaviour of Rickettsia makes the study of its genetics, proteomics and cellular processes very difficult. Hence, isolation remains an important experimental technique that permits the obtention of important yields of bacteria, useful for a broad range of experiments. Isolation of Rickettsia using passages in animals or embryonated eggs has been described for long time; however, it was until the 1990s that faster and more feasible approaches for cell culture were developed. Current isolation approaches are mainly based on shell vial culture, that varies according to the media, atmosphere or temperature conditions. These variations have allowed the establishment of isolates from different pathogenic and non-pathogenic Rickettsia species, using arthropod, animal or human samples. Purification method of bacteria has also witnessed changes alongside the quantification of its load in the resulting isolates, from the laborious and time consuming plaque assays, to the routinary use of real-time polymerase chain reaction (qPCR), which is faster and more accurate. This review discusses various approaches that have been used for the isolation and purification of different Rickettsia species along with the mention of some successful examples. It indicated that a successful strategy for the isolation of Rickettsia requires a careful selection of media, cell lines and culture conditions which now are not as time consuming as used to be.