| Human monocytic ehrlichiosis | |
|---|---|
 | |
| Ehrlichia chaffeensis | |
| Specialty | Infectious diseases  |
Human monocytotropic ehrlichiosis [1] is a form of ehrlichiosis associated with Ehrlichia chaffeensis . [2] This bacterium is an obligate intracellular pathogen affecting monocytes and macrophages. [3]
The most common symptoms are fever, headache, malaise, and muscle aches (myalgia). Compared to human granulocytic anaplasmosis, rash is more common. [4] Laboratory abnormalities include thrombocytopenia, leukopenia, and elevated liver tests.[ citation needed ]
The severity of the illness can range from minor or asymptomatic to life-threatening. CNS involvement may occur. A serious septic or toxic shock-like picture can also develop, especially in patients with impaired immunity. [5]
This disease is known to be caused by tick bites. [6]
Tick exposure is often overlooked. For patients living in high-prevalence areas who spend time outdoors, a high degree of clinical suspicion should be employed.[ citation needed ] Ehrlichia serologies can be negative in the acute period. Polymerase chain reaction is therefore the laboratory diagnostic tool of choice. [7]
If ehrlichiosis is suspected, treatment should not be delayed while waiting for a definitive laboratory confirmation, as prompt doxycycline therapy has been associated with improved outcomes. [8] Doxycycline is the treatment of choice.[ citation needed ]
Presentation during early pregnancy can complicate treatment. [9] Rifampin has been used in pregnancy and in patients allergic to doxycycline. [10]
In the US, human monocytotropic ehrlichiosis occurs across the south-central, southeastern, and mid-Atlantic states, regions where both the white-tailed deer (Odocoileus virginianus) and its ectoparasite, Lone Star ticks ( Amblyomma americanum ), thrive. [11] [12] [13]
Human monocytotropic ehrlichiosis occurs in California in Ixodes pacificus ticks and in Dermacentor variabilis ticks. [14] Nearly 600 cases were reported to the CDC in 2006. In 2001–2002, the incidence was highest in Missouri, Tennessee, and Oklahoma, as well as in people older than 60. [15]
Ehrlichiosis is a tick-borne disease of dogs usually caused by the rickettsial agent Ehrlichia canis. Ehrlichia canis is the pathogen of animals. Humans can become infected by E. canis and other species after tick exposure. German Shepherd Dogs are thought to be susceptible to a particularly severe form of the disease; other breeds generally have milder clinical signs. Cats can also be infected.
Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. The economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide. Most of these pathogens require passage through vertebrate hosts as part of their life cycle. Tick-borne infections in humans, farm animals, and companion animals are primarily associated with wildlife animal reservoirs. Many tick-borne infections in humans involve a complex cycle between wildlife animal reservoirs and tick vectors. The survival and transmission of these tick-borne viruses are closely linked to their interactions with tick vectors and host cells. These viruses are classified into different families, including Asfarviridae, Reoviridae, Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, and Flaviviridae.
Erythema migrans or erythema chronicum migrans is an expanding rash often seen in the early stage of Lyme disease, and can also be caused by southern tick-associated rash illness (STARI). It can appear anywhere from one day to one month after a tick bite. This rash does not represent an allergic reaction to the bite, but rather an actual skin infection of one of the Lyme bacteria species from the genus Borrelia. The rash's name comes from Neo-Latin for "Redness migrating."
Dermacentor variabilis, also known as the American dog tick or wood tick, is a species of tick that is known to carry bacteria responsible for several diseases in humans, including Rocky Mountain spotted fever and tularemia. It is one of the best-known hard ticks. Diseases are spread when it sucks blood from the host. It may take several days for the host to experience symptoms.
A canine vector-borne disease (CVBD) is one of "a group of globally distributed and rapidly spreading illnesses that are caused by a range of pathogens transmitted by arthropods including ticks, fleas, mosquitoes and phlebotomine sandflies." CVBDs are important in the fields of veterinary medicine, animal welfare, and public health. Some CVBDs are of zoonotic concern.
Anaplasma phagocytophilum is a Gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis.
Anaplasmosis is a tick-borne disease affecting ruminants, dogs, and horses, and is caused by Anaplasma bacteria. Anaplasmosis is an infectious but not contagious disease. Anaplasmosis can be transmitted through mechanical and biological vector processes. Anaplasmosis can also be referred to as "yellow bag" or "yellow fever" because the infected animal can develop a jaundiced look. Other signs of infection include weight loss, diarrhea, paleness of the skin, aggressive behavior, and high fever.
Ehrlichiosis is a tick-borne bacterial infection, caused by bacteria of the family Anaplasmataceae, genera Ehrlichia and Anaplasma. These obligate intracellular bacteria infect and kill white blood cells.
Anaplasma is a genus of gram-negative bacteria of the alphaproteobacterial order Rickettsiales, family Anaplasmataceae.
Ehrlichia is a genus of Rickettsiales bacteria that are transmitted to vertebrates by ticks. These bacteria cause the disease ehrlichiosis, which is considered zoonotic, because the main reservoirs for the disease are animals.
Amblyomma americanum, also known as the lone star tick, the northeastern water tick, or the turkey tick, is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly goes unnoticed, remaining attached to its host for as long as seven days until it is fully engorged with blood. It is a member of the phylum Arthropoda, class Arachnida. The adult lone star tick is sexually dimorphic, named for a silvery-white, star-shaped spot or "lone star" present near the center of the posterior portion of the adult female shield (scutum); adult males conversely have varied white streaks or spots around the margins of their shields.
Southern tick-associated rash illness (STARI) is an emerging infectious disease related to Lyme disease that occurs in southeastern and south-central United States. It is spread by tick bites and it was hypothesized that the illness was caused by the bacteria Borrelia lonestari. However, there is insufficient evidence to declare this Borrelia strain as a causative agent.
Ehrlichia chaffeensis is an obligate intracellular, Gram-negative species of Rickettsiales bacteria. It is a zoonotic pathogen transmitted to humans by the lone star tick. It is the causative agent of human monocytic ehrlichiosis.
Ehrlichia ewingii is a species of rickettsiales bacteria. It has recently been associated with human infection, and can be detected via PCR serological testing. The name Ehrlichia ewingii was proposed in 1992.
Human granulocytic anaplasmosis (HGA) is a tick-borne, infectious disease caused by Anaplasma phagocytophilum, an obligate intracellular bacterium that is typically transmitted to humans by ticks of the Ixodes ricinus species complex, including Ixodes scapularis and Ixodes pacificus in North America. These ticks also transmit Lyme disease and other tick-borne diseases.
Ehrlichiosis ewingii infection is an infectious disease caused by an intracellular bacteria, Ehrlichia ewingii. The infection is transmitted to humans by the tick, Amblyomma americanum. This tick can also transmit Ehrlichia chaffeensis, the bacteria that causes human monocytic ehrlichiosis (HME).
Ehrlichia canis is an obligate intracellular bacterium that acts as the causative agent of ehrlichiosis, a disease most commonly affecting canine species. This pathogen is present throughout the United States, South America, Asia, Africa and recently in the Kimberley region of Australia. First defined in 1935, E. canis emerged in the United States in 1963 and its presence has since been found in all 48 contiguous United States. Reported primarily in dogs, E. canis has also been documented in felines and humans, where it is transferred most commonly via Rhipicephalus sanguineus, the brown dog tick.
Ehrlichia Wisconsin HM543746 is an unnamed tick bacterium that spread through Minnesota and Wisconsin in 2009 and is similar to Ehrlichia muris.
Anaplasma bovis is gram negative, obligate intracellular organism, which can be found in wild and domestic ruminants, and potentially a wide variety of other species. It is one of the last species of the Family Anaplasmaceae to be formally described. It preferentially infects host monocytes, and is often diagnosed via blood smears, PCR, and ELISA. A. bovis is not currently considered zoonotic, and does not frequently cause serious clinical disease in its host. This organism is transmitted by tick vectors, so tick bite prevention is the mainstay of A. bovis control, although clinical infections can be treated with tetracyclines. This organism has a global distribution, with infections noted in many areas, including Korea, Japan, Europe, Brazil, Africa, and North America.
In the United States, the National Notifiable Disease Surveillance System (NNDSS) is responsible for sharing information regarding notifiable diseases. As of 2020, the following are the notifiable diseases in the US as mandated by the Centers for Disease Control and Prevention:
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