Babesia
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''Babesia'', also called ''Nuttallia'', is an
apicomplexa The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...
n parasite that infects red blood cells and is transmitted by ticks. Originally discovered by Romanian bacteriologist Victor Babeș in 1888; over 100 species of ''Babesia'' have since been identified. ''Babesia'' comprises more than 100 species of tick-borne parasites that infect erythrocytes (red blood cells) in many vertebrate hosts. ''Babesia'' species infect livestock worldwide, wild and domestic vertebrate animals, and occasionally humans, where they cause the disease babesiosis. In the United States, ''B. microti'' is the most common strain of the few that have been documented to cause disease in humans.


Classification

''Babesia'' is a
protozoan Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically ...
parasite found to infect vertebrate animals, mostly livestock mammals and birds, but also occasionally humans. Common names of the disease that ''B. microti'' causes are Texas cattle fever, redwater fever, tick fever, and Nantucket fever. The disease it causes in humans, babesiosis, is also called piroplasmosis. ''Babesia microti'', however, is not part of the genus ''Babesia''. Due to historical misclassifications, the protozoan has been labeled with many names, including ''Nuttallia,'' and was renamed from ''Babesia microti'' to ''Theileria microti'' based on evidence from 2006. Its
genetic sequence Genetic may refer to: *Genetics, in biology, the science of genes, heredity, and the variation of organisms **Genetic, used as an adjective, refers to genes *** Genetic disorder, any disorder caused by a genetic mutation, whether inherited or de no ...
, published in 2012, shows that the species belongs to neither ''Babesia'' nor ''Theileria,'' but instead to a separate genus. Another "western" group is also separate from core ''Babesia''. The avian ''Babesia'' species are characterized as having ring and amoeboid forms, and fan-shaped or cruciform (cross-shaped) tetrad schizonts. Developing parasites have only been reported in red blood cells.


History

For centuries, the animal disease was known to be a serious illness for wild and domesticated animals, especially cattle. In 1888, Victor Babeș first identified the causative agent in
Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...
and believed it to be due to the bacterium he named ''Haematococcus bovis''. He documented the disease by describing signs of a severe hemolytic illness seen uniquely in cattle and sheep. In 1893, Americans Theobald Smith and Fred Kilborne identified the parasite as the cause of Texas cattle fever, the same disease described by Babeș. They also identified the tick as the transmitting agent, a discovery which first introduced the concept of
arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...
s functioning as
disease vector In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen such as a parasite or microbe, to another living organism. Agents regarded as vectors are mostly blood-sucking ( hematophagous) arthropods such ...
s. It was believed to be a disease that only affected nonhuman mammals, but in 1957, the first case of babesiosis was seen in a human. The person had been splenectomized, as were all people diagnosed with babesiosis until 1969, when the first case of babesiosis was diagnosed in a person who still had their
spleen The spleen (, from Ancient Greek '' σπλήν'', splḗn) is an organ (biology), organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The spleen plays important roles in reg ...
. This proved the parasite was a potential pathogen in anyone.


Genetics

''Babesia'' species show host specificity, allowing many different subspecies of ''Babesia'' to emerge, each infecting a different kind of vertebrate organism. While '' B. bovis'' and '' Babesia bigemina'' prefer to infect cattle in tropical environments, they can infect other animals, such as the
white-tailed deer The white-tailed deer (''Odocoileus virginianus''), also known Common name, commonly as the whitetail and the Virginia deer, is a medium-sized species of deer native to North America, North, Central America, Central and South America. It is the ...
. Therefore, while the organism has the capacity to display host specificity, and thus increase transmission effectiveness, it can still infect a variety of hosts. It achieves this through mutations and natural selection. In different environments, individual protozoa may develop mutations, which when they increase the protozoa's fitness, allow the population to increase in number. This specificity explains why ''Babesia'' species have such great genetic diversity. ''Babesia'' selfishly persists long-term in the host's system: The host gains no benefit from the parasite invasion and only suffers. This allows the parasite to exploit all resources offered by the host, to increase in number, and to increase the rate of transmission. Too lethal an infection results in the host's death and the parasite is unable to spread, which is a loss from an evolutionary standpoint. Different species of ''Babesia'' are able to withstand the stress of the host's immune system. Infection typically stimulates the
innate immune system The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system). The innate immune system is an alternate defense strategy and is the dominant immune s ...
, and not the humoral immune system. This results in control of the infection, but also persistence and not clearance of the parasite.


Genomics

The genome of ''B. microti'' has been sequenced and shows that the species does not belong to either ''Babesia'' or ''Theileria,'' but instead to a separate genus. , it is known that the mitochondrial genome is linear like other sequenced
Apicomplexa The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...
mitochondrial genomes, although it was initially reported that it was circular. Partial
RNA sequencing RNA-Seq (named as an abbreviation of RNA sequencing) is a technique that uses next-generation sequencing to reveal the presence and quantity of RNA molecules in a biological sample, providing a snapshot of gene expression in the sample, also kn ...
of canine piroplasms has identified a number of additional species.


Lifecycle

The lifecycle of ''B. microti'', which is typical of parasites in the genus, requires a biological stage in a rodent or deer host. It is transmitted by ticks of the family Ixodidae between these hosts. To begin, the tick as the definitive host becomes infected itself, as it takes up
gametocyte A gametocyte is a eukaryotic germ cell that divides by mitosis into other gametocytes or by meiosis into gametids during gametogenesis. Male gametocytes are called ''spermatocytes'', and female gametocytes are called ''oocytes''. Development T ...
s when attached for a blood meal. It also introduces the ''Babesia'' into the intermediate host (e.g. cattle) when taking a blood meal. As ''Babesia'' enter the animal's
red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...
s (erythrocytes), they are called sporozoites. Within the red blood cell, the protozoa become cyclical and develop into a trophozoite ring. The trophozoites moult into merozoites, which have a tetrad structure coined a Maltese-cross form. Trophozoite and merozoite growth ruptures the host erythrocyte, leading to the release of vermicules, the infectious parasitic bodies, which rapidly spread the protozoa throughout the blood. Rather than producing more and more trophozoites, some of the merozoites produce gametocytes. The
gametes A gamete ( ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. The name gamete was introduced by the Ge ...
are fertilized in the tick gut and develop into sporozoites in the salivary glands. These are the sporozoites the infected tick introduces when it bites an intermediate host. Even as an incidental host, the phase changes that occur in the parasite are the same within humans as in the biological hosts. ''Babesia'' can be diagnosed at the trophozoite stage, and can also be transmitted from human to human through the tick vector, through blood transfusions, or through congenital transmission (an infected mother to her baby).


Seasonality


Temperature

Cold weather completely interrupts transmission. The emergence of tick-borne diseases has been found to coincide with climate change. The correlation between climate change and the incidence of tick-borne diseases is not known to be strong enough to count as a major factor.


Humidity

High humidity and rainfall accommodate ticks carrying ''Babesia''. This may explain why ''B. bigemina'' infection in cattle in the hilly region of
Meghalaya Meghalaya (; "the abode of clouds") is a states and union territories of India, state in northeast India. Its capital is Shillong. Meghalaya was formed on 21 January 1972 by carving out two districts from the Assam: the United Khasi Hills an ...
has increased. The lifespan and number of generations of ''B. microplus'' correlate with increasing the longevity of larvae and the number of annual generations. Warm, dry weather interferes with the ''Babesia'' lifecycle within the tick. Warm, wet weather increases the intensity of infestation—the population is able to thrive due to the relatively fluid environment, making water and nutrients more accessible.


Transmission

''Babesia'' species are spread through the saliva of a tick when it bites. Already at its nymphal stage, a tick bites into the skin for a blood meal. The tick, if not removed, stays attached for three to four days, with longer periods of feeding associated with a higher probability of acquiring the parasite. The parasite can survive in the tick as it molts through its various developmental stages, resulting in all tick stages being potentially infectious. Some species of ''Babesia'' can be transmitted from a female tick to its offspring before migrating to salivary glands for feeding. ''B. microti'', the most common species in humans, has not been shown to transmit transovarially. Ticks of domestic animals that transmit ''Babesia'' and cause much disease include the very widespread cattle ticks, ''Rhipicephalus'' (''Boophilus'') ''microplus'', and ''R.(B.) decoloratus''. These ticks have a strict one-host feeding cycle on cattle, so the ''Babesia'' can only be transmitted by the transovarial route. In the Americas, ''
Ixodes scapularis ''Ixodes scapularis'' is a hard-bodied tick found in much of the eastern half of North America. It is commonly known as the deer tick, owing to its habit of parasitizing the white-tailed deer. It is also sometimes known as the black-legged tick ( ...
'' is the most common vector. This hard tick, commonly known as a deer tick, is also the vector for other tick-associated illnesses, such as
Lyme disease Lyme disease, also known as Lyme borreliosis, is a tick-borne disease caused by species of ''Borrelia'' bacteria, Disease vector, transmitted by blood-feeding ticks in the genus ''Ixodes''. It is the most common disease spread by ticks in th ...
. Many species of ''Babesia'' only infect nonhuman mammalian hosts, most commonly cattle, horses, and sheep. ''B. microti'' and ''B. divergens'' are the two main pathogenic species in humans. Their reservoirs are theorized to be the white-footed mouse (''Peromyscus leucopus''), voles from the ''Microtus'' genus, and the white-tailed deer (''Odocoileus virginianus''). These woodland species are hypothesized reservoirs because although they are known to harbor the disease, complete reservoir competence has not yet been shown. Most cases of transmission between humans are attributed to a tick vector. As of 2003, the
Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...
(CDC) acknowledged more than 40 cases of babesiosis contracted from transfusions of packed red blood cells (PRBC), as well as two infections documented from organ transplantation. PRBC transfusions that cause infections were identified through testing the blood donor for ''B. microti'' antibodies. The occurrence of ''Babesia'' transmission through PRBC blood transfusions puts pressure on governmental organizations (such as the CDC) to heighten standard measures for screening blood donations. Transmission is also possible through congenital transmission (from an infected mother to her baby). As symptoms may not appear, many women may not be aware they are infected during pregnancy, so a measurement of congenital transmission rate is not known at this time. Currently, no vectors for avian ''Babesia'' have been identified, but they are assumed to be ticks. ''Babesia'' species require competent vertebrate and invertebrate hosts to maintain transmission cycles.


Epidemiology

Of the species to infect humans, ''B. microti'' is most common in the Americas, whereas ''B. divergens'' is the predominant strain found in Europe.
Endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
areas are regions of tick habitat, including the forest regions of the Northeastern United States and temperate regions of Europe. Ixodidae, the tick vectors of ''B. microti'', also transmit the better-known '' Borrelia burgdorferi'', the causative agent of Lyme disease. For reasons that remain unclear, in areas endemic to both Lyme disease and babesiosis, Lyme disease transmission prevails and is more predominant in the region. Prevalence of babesiosis in malaria-endemic regions remains unknown due to the likelihood of misdiagnosis as malaria. As the disease results in a high number of asymptomatic individuals, many populations can possess high
seroprevalence Seroprevalence is the number of persons in a population who test positive for a specific disease based on serology (blood serum) specimens, often presented as a percent of the total specimens tested or as a proportion per 100,000 persons tested. As ...
without much documentation of illness. For example, in Rhode Island and Nantucket, seroprevalence has been measured to be 20–25%. Prevalence of babesiosis is mostly documented from May to September, when tick activity in endemic regions is high. The avian ''Babesia'' include 15 species, and four ''Babesia'' species have been reported from sea hosts. ''B. poelea'' was described from brown boobies (''Sula leucogaster'') on Sand Island, Johnston Atoll, Central Pacific. ''B. poelea'' was reported from a masked booby (''Sula dactylatra melanops'') from Desnoeufs Island, Amirantes,
Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...
. ''B. peircei'' has been observed in two species of penguins, the jackass penguin (''Sphenicus demersus'') from South Africa and the
little penguin The little penguin (''Eudyptula minor'') is the smallest species of penguin. It originates from New Zealand. It is commonly known as the fairy penguin, little blue penguin, or blue penguin, owing to its slate-blue plumage and is also known by ...
(''Eduyptula minor'') from southern Australia. ''B. bennetti'' was associated from the yellow-legged gull (''Larus cachinnans'') from Benidorm Island off the coast of Spain. ''B. uriae'' was found in common murres in California. About 40 cases of human babesiosis, caused by intraerythrocytic protozoans (protozoa inside red blood cells) of the genus ''Babesia'', were reported in Europe.


Disease

Bovine babesiosis caused by '' B. bovis'' is an important constraint for cattle industries worldwide.


In humans

Signs of infection with ''B. microti'' usually arise one to eight weeks after a bite from an infectious tick. Infections from ''B. divergens'' have a shorter latent period, usually ranging from one to three weeks. The severity of ''B. microti'' infections varies. For 25% of cases in adults and 50% of cases in children, the disease is asymptomatic or mild with flu-like symptoms. In other cases, symptoms are characterized by irregular fevers, chills, headaches, general lethargy, pain, and
malaise In medicine, malaise is a feeling of general discomfort, uneasiness or lack of wellbeing and often the first sign of an infection or other disease. It is considered a vague termdescribing the state of simply not feeling well. The word has exist ...
. In severe cases, effects of parasitic multiplication, symptoms such as hemolytic anemia,
jaundice Jaundice, also known as icterus, is a yellowish or, less frequently, greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving ...
, shortness of breath, and hemoglobinuria have been documented. Individuals with normal immune function and healthy spleens often recover without treatment. Splenectomized patients are more susceptible to contracting the disease and can die within five to eight days of symptom onset. They have severe hemolytic anemia, and occasional
hepatomegaly Hepatomegaly is enlargement of the liver. It is a non-specific sign (medicine), medical sign, having many causes, which can broadly be broken down into infection, hepatic tumours, and metabolic disorder. Often, hepatomegaly presents as an abdomin ...
has been documented. Parasitemia levels can reach up to 85% in patients without spleens, compared to 1–10% in individuals with spleens and effective immune systems. Complications include acute respiratory failure,
congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically pr ...
, and
kidney failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...
. Infections can be fatal in 5–10% of hospitalized patients, with increased risk of death in the immunosuppressed, the elderly, and those also infected with Lyme disease. ''B. divergens'' infections have a much higher fatality rate (42%) and present with more severe symptoms. Infected individuals experience hemoglobinuria followed by jaundice, a persistently high fever, chills, and sweats. If left untreated, ''B. divergens'' infections can develop into shock-like symptoms with
pulmonary edema Pulmonary edema (British English: oedema), also known as pulmonary congestion, is excessive fluid accumulation in the tissue or air spaces (usually alveoli) of the lungs. This leads to impaired gas exchange, most often leading to shortness ...
and kidney failure. In birds The pathogenicity of ''B. uriae'' for murres is currently unknown. Birds were found with
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...
s, anemia and respiratory difficulty, and tissues of avian hosts were affected. ''B. peircei'' infections can cause mild anemia, leukocytosis, and impairment of
hepatic function Liver function tests (LFTs or LFs), also referred to as a hepatic panel or liver panel, are groups of blood tests that provide information about the state of a patient's liver. These tests include prothrombin time (PT/INR), activated Partial Th ...
in African penguins.


Diagnostic tests

As a protozoan parasite, ''Babesia'' infection can be identified through blood culture, direct examination in blood smear and PCR.


Morphology

''Babesia'' species enter
red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...
s (erythrocytes) at the sporozoite stage. Within the red blood cell, the protozoa become cyclical and develop into a trophozoite ring. The trophozoites moult into merozoites, which have a tetrad structure coined a Maltese-cross form. This tetrad morphology seen with Giemsa staining of a thin blood smear is unique to ''Babesia'', and distinguishes it from ''
Plasmodium falciparum ''Plasmodium falciparum'' is a Unicellular organism, unicellular protozoan parasite of humans and is the deadliest species of ''Plasmodium'' that causes malaria in humans. The parasite is transmitted through the bite of a female ''Anopheles'' mos ...
'', a protozoan of similar morphology that causes malaria. Trophozoite and merozoite growth ruptures the host erythrocyte, leading to the release of vermicules, the infectious parasitic bodies, which rapidly spread the protozoa throughout the blood. It is important to pay attention to particular morphologies of ''Babesia'' in blood smears, because of its great similarity to the malarial parasite ''Plasmodium falciparum''. This has resulted in many patients with babesiosis being misdiagnosed. The few distinguishing factors for ''Babesia'' include protozoa with varying shapes and sizes, the potential to contain
vacuole A vacuole () is a membrane-bound organelle which is present in Plant cell, plant and Fungus, fungal Cell (biology), cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water ...
s, and the lack of pigment production. Trophozoites appearing in a tetrad formation within an erythrocyte are also indicative of ''Babesia''. Despite much study of babesiosis and malaria, misdiagnosis with blood smear can be frequent and problematic. To supplement a blood smear, diagnoses should be made with an indirect fluorescent antibody (IFA) test, which has a much higher specificity than stained blood smears, with antibody detection in 88-96% of infected patients. Diagnostic measures through antibody testing are also particularly useful for identifying serum prevalence in asymptomatic individuals. Due to the transmissibility of ''Babesia'' through blood transfusions, IFA testing would be an effective means of screening for the disease in blood donations. Historically, babesiosis diagnosis was carried out with xenodiagnosis in
hamster Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian ...
s for ''B. microti'' and in gerbils for ''B. divergens''. This diagnostic technique has been abandoned in favor of faster diagnostic measures.


Treatment

Several methods are available to manage and treat babesiosis in animals. In humans, many spontaneously recover, having only experienced mild symptoms not diagnosed as the disease. This is almost always seen in ''B. microti'' infections, which are generally more common in the United States. For ''B. divergens'' and more severe ''B. microti'' infections, the standard treatment historically for symptomatic individuals was oral or intravenous clindamycin with oral
quinine Quinine is a medication used to treat malaria and babesiosis. This includes the treatment of malaria due to ''Plasmodium falciparum'' that is resistant to chloroquine when artesunate is not available. While sometimes used for nocturnal leg ...
. With the results of research completed in 2000, however, treatment regimens have been increasingly leaning towards oral atovaquone with oral
azithromycin Azithromycin, sold under the brand names Zithromax (in oral form) and Azasite (as an eye drop), is an antibiotic medication used for the treatment of several bacterial infections. This includes otitis media, middle ear infections, strep throa ...
. The latter are preferred, as they are equally effective in all but the most severe cases and exhibit fewer associated adverse reactions. In severe cases, blood exchange transfusions have been performed to lower the parasitic load in an individual. Other measures include addressing and correcting abnormal clinical signs. In seabirds, primaquine has been used in a study to show effective treatment on infected hosts. Treatment for babesiosis consisted of primaquine (1 mg/kg PO q24h for 10 days; primaquine
phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...
1.76%m/v in stabilized solution, Primaquin Solution, MedPet Ltd, Benrose, South Africa). After, treatment was followed by a phospholipid supplement (1 capsule/bird PO q24h for 12 days; deoiled, enriched
phospholipid Phospholipids are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typ ...
s from soybeans, 300 mg/capsule, Essentiale Extreme,
Sanofi Aventis Sanofi S.A. is a French multinational pharmaceutical and healthcare company headquartered in Paris, France. The corporation was established in 1973 and merged with Synthélabo in 1999 to form Sanofi-Synthélabo. In 2004, Sanofi-Synthélabo merg ...
Ltd,
Midrand Midrand is a town in central Gauteng, South Africa. It is situated in-between Centurion, Gauteng, Centurion and Sandton. Formerly an independent municipality, Midrand now forms part of the City of Johannesburg Metropolitan Municipality. History ...
, South Africa); as an attempt to mitigate potential hepatotoxic effects of primaquine. To prevent transmission of ''Babesia'' and other tickborne pathogens, all birds with visible ectoparasites are treated with pesticide powder ( carbaryl 50 g/kg) upon admission, and the facilities are thoroughly cleaned on a daily basis.


Prevention in animals

In 1906, efforts were made to eradicate the tick vector of bovine babesiosis in the United States. This eradication was recorded as being successfully completed. The disease was eradicated from the United States by 1943, except for a permanent quarantine area along the Texas/Mexico border, where cattle fever ticks are still found.Cattle Fever Ticks, USDA https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/cattle-fever Effective control can be achieved by
vaccination Vaccination is the administration of a vaccine to help the immune system develop immunity from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating ...
with live attenuated
phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properti ...
of the parasite. The vaccines have a number of drawbacks, so better, safer vaccines are still being researched. In recent years, a number of parasite proteins with immunogenic potential have been discovered. Through
polymerase chain reaction The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed st ...
, genetic sequencing, and bioinformatics analysis of the genes, a high degree of conservation (98–100%) was found among Brazilian isolates of ''B. bovis'' and the T2Bo isolate. Thus, these genes are considered for inclusion in a recombinant cocktail vaccine for cattle babesiosis caused by ''B. bovis''.


Prevention in humans

The most effective public health measure for ''Babesia'' is to avoid tick exposure. This can be through personal prevention such as avoiding tick-infested areas (especially during high tick season between May and September), remaining covered with light clothing, searching for ticks after being outdoors, and removing discovered ticks from the skin. Other measures include applying
DEET ''N'',''N''-Diethyl-''meta''-toluamide, also called diethyltoluamide or DEET (, from DET, the initials of di- + ethyl + toluamide), is the oldest, one of the most effective, and most common active ingredients in commercial insect repellents. ...
, a common repellent that is effective against ticks and insects. (For people who react adversely to DEET, alternative insect repellents should be used.) On a state level, if health departments are particularly motivated, tick elimination is a possibility. In 1906, efforts were made to eradicate the tick vector of the bovine disease form of babesiosis in the United States. This eradication was recorded as being successfully completed four decades later. Complete eradication through vector control would be a long-term project, which would significantly reduce the prevalence of both babesiosis and Lyme disease, but as public health departments are often short on funding, preventive measures are more recommended. Due to the relatively low prevalence of the human disease and the presence of several reservoirs, babesiosis has not been a candidate for vaccines. In regions where ticks of domestic animals are routinely controlled with chemical
acaricide Acaricides are pesticides that kill members of the arachnid subclass '' Acari'', which includes ticks and mites. Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields. Termi ...
s to reduce incidence of infection with ''B. bovis'' and ''B. bigemina'', the risk to humans from these parasites is reduced.


References


External links

*
Fact Sheet from the New York State Department of Health



CDC Laboratory Identification of Parasites of Public Health Concern: Babesiosis
{{Authority control Apicomplexa genera Parasites of humans Tick-borne diseases