What Is Spotted Fever?
Spotted fevers are caused by rickettsia species that are closely related. They are pleomorphic and gram-negative and belong to the family Rickettsiaceae. The genus rickettsia has at least 25 validated species. They contain several pathogens, which are majorly transmitted by ticks. Mediterranean spotted fever is common in the area surrounding the Mediterranean basin. It also includes regions of the Middle East, northern Africa, and southern Europe, northern and central Europe. The tick vector survives in dogs and acts as a transmitter to humans.
What Is Israeli Spotted Fever?
Tick-transmitted rickettsia cause Israeli spotted fever and belong to the rickettsia conorii complex. It was first isolated from ticks and humans in the year 1974. Initially, this disease was widely distributed in Israel alone. However, this organism has been isolated from patients with Mediterranean spotted fever in countries like Portugal. So it is inferred that the disease is not only restricted to Israel but spread among other places like Tunisia, Libya, Portugal, Italy, and the Iberian peninsula. Spotted fever can have fatal morbidity in even young and healthy adults. Transmission risk depends on the tick prevalence, the density of the tick population, and the possibility of humans acquiring tick transmission.
What Is the Significance of This Disease?
Rickettsia conorii subspecies israelensis, the causative agent for Israeli spotted fever, is the most virulent strain and has a high fatality rate in hospitalized patients. But around six percent of the cases are severe, and the death rate is approximately 2.5 percent in the reported cases. Ticks multiply in warm, humid months. Many cases of Israeli spotted fever have been diagnosed postmortem in children and adults in Israel through animal inoculation, cell culture methods, and immunohistochemical detection of the rickettsial antigen at autopsy in paraffin-embedded tissue. Rickettsiosis, a group of diseases caused by rickettsia, is always susceptible to febrile travelers.
What Are the Signs and Symptoms of This Disease?
Affected patients exhibit a maculopapular rash in the soles of the feet and palms of the hands. These rashes can become hemorrhagic. Fever is present, and in severe cases, there can be a multiorgan failure, including acute liver failure, kidney failure, purpura fulminans, and encephalitis (brain inflammation). Purpura fulminans is a purpuric rash that appears as bruising, blood spots, and skin discoloration.
Gastrointestinal symptoms such as nausea and vomiting were prominent in patients with a fatal course of Israeli spotted fever. In addition, an eschar (lesion occurring at the tick-bite site) can occur. Still, it is less remarkable in patients with Israeli spotted fever, and it is an obstacle for physicians to conclude a definitive diagnosis.
This disease is still under study, and the symptoms are specific to each individual. However, based on a study conducted on affected patients in Israel, about 81 percent of the patients had a fever, 77 percent had a rash, and 44 percent had a headache. In addition, 50 percent of the patients had gastrointestinal symptoms, and 27.3 percent died of multiorgan failure.
How Is Israeli Spotted Fever Diagnosed?
Spotted fevers are mostly diagnosed tentatively based on presumption by considering the symptoms and history, and treatment is started before the diagnosis with laboratory tests. However, most of the cases can be confirmed by serology.
Skin biopsy from eschar is used to detect the rickettsia species, but this technique is painful, invasive, and difficult to perform in inaccessible body parts. Instead, a serum antibody assay is done to distinguish between subspecies of the bacterium. Skin biopsy is taken and tested by PCR (polymerase chain reaction). Serologic analysis was done to check reactivity, but they were not helpful, as they can be non-reactive in some affected patients. PCR tests will help allow the detection of rickettsial DNA copies and provide faster diagnosis.
How Is Israeli Spotted Fever Managed?
The standard treatment protocol for spotted fever is antimicrobial therapy. Tetracyclines are mostly used; however, due to teeth staining and bone toxicity in children, they are substituted with macrolides. However, antibiotics used for rickettsial infections are Tetracycline and Chloramphenicol. Symptomatic treatment is provided in patients, as the symptoms are unique in each individual.
How to Prevent Spotted Fevers?
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Avoiding tick bites is considered to be the cornerstone of prevention for tick-borne rickettsioses.
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Protective clothing should be worn when handling pets.
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Long-sleeve shirts should be worn, and the trousers should be tucked inside the socks to prevent tick bites when visiting endemic countries.
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Wear light-colored clothing, as ticks can be more visible on light-colored dresses.
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Clothes should be treated with Permethrin, an acaricide.
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A tick repellent can also be used. However, they are effective only in short intervals of time. Reapplication should be done in cases of tick-prone areas.
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After visiting a tick-infested surrounding, the clothing should be decontaminated.
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People handling dogs or visiting tick-habitat should check for any tick bites often periodically. If any are present, they must be removed using gloved hands or a fine-tipped tweezer. In case of non-availability of gloves, tissue or paper towel can be used and disposed of.
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According to the CDC (Centres for Disease Control and Prevention), ticks should not be killed using heat, matchsticks, or petroleum jelly, as the tick can release additional saliva and could increase the risk of infection.
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Tick bites and affected areas must be disinfected, and hand washing is mandatory after removal.
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When the infection-causing tick is used for examination, they have to be frozen and stored in a plastic bag to identify the species.
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Tick removal from both infected humans and pets is necessary to prevent further infection spread.
Conclusion:
The incidence of spotted fevers in Israel has reduced drastically due to the implementation of anti-tick measures. Health service utilization and tick exposure prevention will help reduce the incidence of Israeli spotted fever. However, proper tick prevention methods must be followed, and the ticks should not be squeezed, punctured, or crushed. In healthcare facilities, when they doubt a spotted fever incident, patients should be started with treatment as delayed treatment can cause fatality in many individuals.
