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Clinical Microbiology Reviews Mar 2020Increases in tick-borne disease prevalence and transmission are important public health issues. Efforts to control these emerging diseases are frustrated by the struggle... (Review)
Review
Increases in tick-borne disease prevalence and transmission are important public health issues. Efforts to control these emerging diseases are frustrated by the struggle to control tick populations and to detect and treat infections caused by the pathogens that they transmit. This review covers tick-borne infectious diseases of nonrickettsial bacterial, parasitic, and viral origins. While tick surveillance and tracking inform our understanding of the importance of the spread and ecology of ticks and help identify areas of risk for disease transmission, the vectors are not the focus of this document. Here, we emphasize the most significant pathogens that infect humans as well as the epidemiology, clinical features, diagnosis, and treatment of diseases that they cause. Although detection via molecular or immunological methods has improved, tick-borne diseases continue to remain underdiagnosed, making the scope of the problem difficult to assess. Our current understanding of the incidence of tick-borne diseases is discussed in this review. An awareness of the diseases that can be transmitted by ticks in specific locations is key to detection and selection of appropriate treatment. As tick-transmitted pathogens are discovered and emerge in new geographic regions, our ability to detect, describe, and understand the growing public health threat must also grow to meet the challenge.
Topics: Animals; Clinical Laboratory Techniques; Humans; Tick-Borne Diseases; Ticks
PubMed: 31896541
DOI: 10.1128/CMR.00083-18 -
Pathogens (Basel, Switzerland) Sep 2021are tick-borne intra-erythrocytic parasites and the causative agents of babesiosis. , which are readily transfusion transmissible, gained recognition as a major risk to... (Review)
Review
are tick-borne intra-erythrocytic parasites and the causative agents of babesiosis. , which are readily transfusion transmissible, gained recognition as a major risk to the blood supply, particularly in the United States (US), where is endemic. Many of those infected with remain asymptomatic and parasitemia may persist for months or even years following infection, such that seemingly healthy blood donors are unaware of their infection. By contrast, transfusion recipients are at high risk of severe babesiosis, accounting for the high morbidity and mortality (~19%) observed in transfusion-transmitted babesiosis (TTB). An increase in cases of tick-borne babesiosis and TTB prompted over a decade-long investment in blood donor surveillance, research, and assay development to quantify and contend with TTB. This culminated in the adoption of regional blood donor testing in the US. We describe the evolution of the response to TTB in the US and offer some insight into the risk of TTB in other countries. Not only has this response advanced blood safety, it has accelerated the development of novel serological and molecular assays that may be applied broadly, affording insight into the global epidemiology and immunopathogenesis of human babesiosis.
PubMed: 34578209
DOI: 10.3390/pathogens10091176 -
Pathogens (Basel, Switzerland) Jul 2019The incidence and geographic distribution of human babesiosis is growing in the U.S. Its major causative agent is the protozoan parasite, . is transmitted to humans... (Review)
Review
The incidence and geographic distribution of human babesiosis is growing in the U.S. Its major causative agent is the protozoan parasite, . is transmitted to humans primarily through the bite of ticks, which are vectors for a number of other pathogens. Other routes of transmission are blood transfusion and in rare cases of mother-to-foetus transmission, through the placenta. This review discusses the current literature on mammalian coinfection with and , the causative agent Lyme disease.
PubMed: 31370180
DOI: 10.3390/pathogens8030117 -
Pathogens (Basel, Switzerland) Sep 2021Parasites from diverse hosts morphologically identified as have previously been shown to belong to a paraphyletic species complex. With a growing number of reports of... (Review)
Review
Parasites from diverse hosts morphologically identified as have previously been shown to belong to a paraphyletic species complex. With a growing number of reports of -like parasites from across the world, this paper seeks to report on the current knowledge of the diversity of this species complex. Phylogenetic analysis of 18S rDNA sequences obtained from GenBank shows that the diversity of the species complex has markedly increased and now encompasses at least five distinct clades. This cryptic diversity calls into question much of our current knowledge of the life cycle of these parasites, as many biological studies were conducted before DNA sequencing technology was available. In many cases, it is uncertain which -like parasite was studied because parasites from different clades may occur sympatrically and even share the same host. Progress can only be made if future studies are conducted with careful attention to parasite identification and PCR primer specificity.
PubMed: 34578201
DOI: 10.3390/pathogens10091168 -
Pathogens (Basel, Switzerland) Nov 2021Babesiosis is an emerging tick-borne disease caused by intraerythrocytic protozoa that are primarily transmitted by hard-bodied (ixodid) ticks and rarely through blood... (Review)
Review
Babesiosis is an emerging tick-borne disease caused by intraerythrocytic protozoa that are primarily transmitted by hard-bodied (ixodid) ticks and rarely through blood transfusion, perinatally, and organ transplantation. More than 100 species infect a wide spectrum of wild and domestic animals worldwide and six have been identified as human pathogens. is the predominant species that infects humans, is found throughout the world, and causes endemic disease in the United States and China. and -like agent also cause endemic disease in China. is the predominant species in Europe where fulminant cases have been reported sporadically. The number of infections has been increasing globally in recent decades. In the United States, more than 2000 cases are reported each year, although the actual number is thought to be much higher. In this review of the epidemiology of human babesiosis, we discuss epidemiologic tools used to monitor disease location and frequency; demographics and modes of transmission; the location of human babesiosis; the causative species in the Americas, Europe, Asia, Africa, and Australia; the primary clinical characteristics associated with each of these infections; and the increasing global health burden of this disease.
PubMed: 34832603
DOI: 10.3390/pathogens10111447 -
Pathogens (Basel, Switzerland) Sep 2021Babesiosis is attracting increasing attention as a worldwide emerging zoonosis. The first case of human babesiosis in Europe was described in the late 1950s and since... (Review)
Review
Babesiosis is attracting increasing attention as a worldwide emerging zoonosis. The first case of human babesiosis in Europe was described in the late 1950s and since then more than 60 cases have been reported in Europe. While the disease is relatively rare in Europe, it is significant because the majority of cases present as life-threatening fulminant infections, mainly in immunocompromised patients. Although appearing clinically similar to human babesiosis elsewhere, particularly in the USA, most European forms of the disease are distinct entities, especially concerning epidemiology, human susceptibility to infection and clinical management. This paper describes the history of the disease and reviews all published cases that have occurred in Europe with regard to the identity and genetic characteristics of the etiological agents, pathogenesis, aspects of epidemiology including the eco-epidemiology of the vectors, the clinical courses of infection, diagnostic tools and clinical management and treatment.
PubMed: 34578196
DOI: 10.3390/pathogens10091165 -
Pathogens (Basel, Switzerland) Jan 2022Human babesiosis results from a combination of tick tropism for humans, susceptibility of a host to sustain development, and contact with infected ticks. Climate... (Review)
Review
Human babesiosis results from a combination of tick tropism for humans, susceptibility of a host to sustain development, and contact with infected ticks. Climate modifications and increasing diagnostics have led to an expanded number of species responsible for human babesiosis, although, to date, most cases have been attributed to and . These two species have been extensively studied, and in this review, we mostly focus on the antigens involved in host-parasite interactions. We present features of the major antigens, so-called Bd37 in and BmSA1/GPI12 in , and highlight the roles of these antigens in both host cell invasion and immune response. A comparison of these antigens with the major antigens found in some other Apicomplexa species emphasizes the importance of glycosylphosphatidylinositol-anchored proteins in host-parasite relationships. GPI-anchor cleavage, which is a property of such antigens, leads to soluble and membrane-bound forms of these proteins, with potentially differential recognition by the host immune system. This mechanism is discussed as the structural basis for the protein-embedded immune escape mechanism. In conclusion, the potential consequences of such a mechanism on the management of both human and animal babesiosis is examined.
PubMed: 35056047
DOI: 10.3390/pathogens11010099 -
Pathogens (Basel, Switzerland) Jan 2022and are apicomplexan parasites that cause established and emerging diseases in humans, domestic and wild animals. These protozoans are transmitted by Ixodid ticks... (Review)
Review
and are apicomplexan parasites that cause established and emerging diseases in humans, domestic and wild animals. These protozoans are transmitted by Ixodid ticks causing babesiosis or theileriosis, both characterized by fever, hemolytic anemia, jaundice, and splenomegaly. In North America (NA), the most common species affecting humans is , which is distributed in the Northeastern and Upper Midwestern United States (US), where the tick vector is established. In livestock, and are the most important pathogens causing bovine babesiosis in tropical regions of Mexico. Despite efforts toward eradication of their tick vector, , and present a constant threat of being reintroduced into the southern US and represent a continuous concern for the US cattle industry. Occasional outbreaks of , and have occurred in horses and cattle, respectively, in the US, with significant economic implications for livestock including quarantine, production loss, and euthanasia of infected animals. In addition, a new species, , has been recently discovered in horses from the Mexico-US border. Domestic dogs are hosts to at least four species of in NA that may result in clinical disease that ranges from subclinical to acute, severe anemia. Herein we review the pathogenesis, diagnosis, and epidemiology of the most important diseases caused by and to humans, domestic and wild animals in Canada, the US, and Mexico.
PubMed: 35215111
DOI: 10.3390/pathogens11020168 -
Pathogens (Basel, Switzerland) Sep 2021Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human... (Review)
Review
Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human transmission through blood transfusion, babesiosis is becoming a rising public health concern. The current arsenal for the treatment of human babesiosis is limited and consists of combinations of atovaquone and azithromycin or clindamycin and quinine. These combination therapies were not designed based on biological criteria unique to parasites, but were rather repurposed based on their well-established efficacy against other apicomplexan parasites. However, these compounds are associated with mild or severe adverse events and a rapid emergence of drug resistance, thus highlighting the need for new therapeutic strategies that are specifically tailored to parasites. Herein, we review ongoing babesiosis therapeutic and management strategies and their limitations, and further review current efforts to develop new, effective, and safer therapies for the treatment of this disease.
PubMed: 34578153
DOI: 10.3390/pathogens10091120 -
Pathogens (Basel, Switzerland) Sep 2021Fifty years ago, the index case of human babesiosis due to was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called "Nantucket fever" due... (Review)
Review
Fifty years ago, the index case of human babesiosis due to was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called "Nantucket fever" due to its seeming restriction to Nantucket and the terminal moraine islands of southern New England, has emerged across the northeastern United States to commonly infect people wherever Lyme disease is endemic. We review the history of babesiosis on Nantucket, analyze its epidemiology and ecology there, provide summaries of the first case histories, and comment on its future public health burden.
PubMed: 34578191
DOI: 10.3390/pathogens10091159