What is Bartonellosis?
Bartonellosis combines a group of human diseases caused by gram-negative aerobic, optionally intracellular bacteria that need hemin or red blood cell splitting products for their growth.
Causes of Bartonellosis
Since 1993, Bartonella has been classified in the a-2 subgroup of proteobacteria of the Bartonellaceae family, phylogenetically most related to the Brucella genus, which partly explains the polymorphism of the clinical picture of the diseases they cause. For humans, the pathogens are 5 independent species of Bartonella of varying degrees of virulence.
In nature, Bartonelles circulate among mouse-like rodents, rats, members of the cat family (cats, pumas) and dogs, causing them to have a persistent infection with asymptomatic course and prolonged months-long bacteremia. In humans, acute polymorphic in the clinical picture (Volyn or trench fever, Carrion’s disease, synaptic syndrome – Oroya fever), subacute (cat scratch disease) and chronic (bacillary angiomatosis, Peruvian wart, purple hepatitis, endocarditis, occipital sinuses, chronic hepatitis, bacillary angiomatosis, Peruvian wart, purple hepatitis, endocarditis, occipital sinuses, and hepatitis; diseases.
Story. Chronologically, diseases caused by Bartonella were known much earlier than the discovery and isolation of pathogens themselves. The causative agents of these and other bartonellosis have been discovered, isolated and identified throughout the twentieth century, beginning in 1916.
Morphology, identification, cultivation of Bartonella. Bartonella species (until 1993 – Rochalimaea spp. And others) are microscopically represented mainly by short sticks, 0.3-0.5×1.0-3.0 mm in size. In sections of infected tissues can be curved, pleomorphic, grouped into compact clusters (clusters). Rounded shapes reach 1.5 mm in diameter. They are painted according to Romanovsky-Giemsa; in biopsy specimens from tissues – by dye using Warthing Starry silver; perceived as acridine dye, which is used in immunochemical studies. For B. bacilliformis, 1–4 flagella are located on one of the poles of the cell, and therefore it is mobile; one monopolar flagellum was observed for B. henselae; or just drank. Bacteria have a clearly structured three-layer shell; the latter contains up to 12 proteins with a molecular weight from 174 to 28 kDa. The size of the genome is relatively small, in the range of 1700-2174 in p; the ratio of guanine and cytosine – 38,5-41,0 mol.%. Bartonella multiplication occurs by simple transverse division.
In the body of the sensitive hosts, Bartonella grows on the surface of cells, and red blood cells and endothelial cells of the vascular system and endocardium are introduced and colonized. The biological feature of Bartonella is their unique ability to stimulate the proliferation of endothelium cells and the growth of small vessels in their capillary part, which leads to angiomatosis.
By the nature of nutrition Bartonella are aerobic hematotrophs, demanding on the composition of nutrient media. Outside the human body and rodents, their cultivation can be carried out in body lice (B. quintana), cat fleas (B. henselae), and also on solid and semi-liquid nutrient media enriched with 5-10% of human or animal blood.
During the initial isolation of bartonella from biological samples (blood, biopsy specimens of lymph nodes, abnormal growths on heart valves, papules and other affected organs), a sick person needs a long, up to 15-45 days or more, keeping agar plates planted under optimal growth conditions.
Bartonella isolation from patients’ blood, for example, in connection with endocarditis with negative results of seeding on other bacteria, or lymphadenopathy after scratching or biting a kitten by a kitten, is greatly facilitated if the endothelial cell lines of other animals are used, as well as such a simple technique as centrifuging blood with simultaneous destruction of red blood cells.
Ecology. Bartonella ecology has not been studied enough. The endemicity of the causative agent of Carrion’s disease, B. bacilliformis, is unequivocally established. It is distributed only in the Northwest of South America in the mountainous regions of the Andes, protected from Pacific winds, at altitudes of 600–2500 m above sea level, geographically attached to Peru, partly of Colombia and Ecuador. The life cycle of Bartonella data is associated with the South American species of phlebotomus mosquitoes, namely, Lutzomia noguchi, L. verrucarum and others, as well as local rodents.
The most common, apparently, are pathogens of cat scratch and trench fever, which are carried, respectively, by cat fleas and human lice. The latter are almost ubiquitous insects, their involvement in Bartonella Quintan and Henseli transmissions in the human body has been proven and, obviously, bartenellosis caused by these two types of microorganisms are distributed throughout the globe within the places of permanent human habitat. In particular, there is a high (up to 68.1%) bacteremia among cats and kittens associated with B. henselae in some states of the USA, as well as in Germany, especially among animals (up to 89%) from those families in which the children or the owners themselves cats suffered cat scratch disease.
A wide search for bartonella in the natural population of rodents in various countries (USA, Bolivia, Paraguay, British Columbia (Canada), Poland and others) revealed a high prevalence of bartonelles in the natural population of rodents, felines (cougars) and dogs (coyotes). The study of ecology and epidemiology of Bartonelle continues.
Compared to the most pathogenic for humans, B. bacilliformis and B. quintana, it is assumed that a significant reservoir of these pathogens is a person, since asymptomatic and mild forms of the infection have been reported, accompanied by prolonged bacterial carriers. The natural reservoir for B. elizabethae also appears to be small wild mammals.
Epidemiology. Mandatory registration of bartonella does not exist. It is known that during the First World War, an epidemic of trench fever broke out in the theater of operations in Europe, affecting at least 1 million soldiers. During the Second World War, it was revived in an epidemic form, but on a much smaller scale. About 80 thousand people got sick. With the end of the Second World War, outbreaks of trench fever have ceased. The age of infection with B. quintana was reported in the early 1990s, when the causative agent was identified as the cause of opportunistic infection in HIV-infected individuals. Serological and molecular genetic studies in different countries, including Russia, have revealed the latent circulation of the pathogen among the population and its presence in the lice population. In the population of Ukraine, specific antibodies to quintan bartonella were detected in all age groups in the range of 1.48-2.48%, in France – in 0.6% of the examined, and endocarditis due to this type of bartonella was confirmed in 76.4% in the group patients with an unknown etiology of suffering (1995-1998).
Epidemic trench fever is associated with human lice in epidemic typhus; it is caused by mechanical rubbing of infected feces into the skin scratching. In feces of lice, Bartonella Quintan retains its vitality for an exceptionally long time — up to 1312 days. The natural reservoir of Bartonella Quintana has not yet been established, the only source of infection is considered to be man. In lice, in contrast to typhous rickettsiosis, bartonellosis is asymptomatic, the microorganism lasts for life (up to 30-45 days), transovarial transmission is absent. A person, in addition to acutely febrile illness, may have a long-term (up to 2-5 years) hidden asymptomatic carriage or in combination with chronic lymphadenopathy and endocarditis.
Fleas Cfenocephalides felis, as well as body lice, unlike ticks, feed many times during the life cycle and are illegible in relation to their host. As a result, they alternately suck on cats or rodents, in their environment are easily infected with Bartonella. In their bodies, Bartonella Hensely persists for more than a year without affecting behavior and lifestyle. In search of food insects attack humans.
The true number of people suffering from bartonella, caused by Bartonella Hensel, remains unclear. But it is known that in the United States, for example, in the early 1990s, the most widespread rickettsiosis in this country — the Rocky Mountain spotted fever — was recorded at a level exceeding 1000 cases annually, while the incidence of cat scratch disease was estimated at 22,000 cases, of which 2000 – were hospitalized.
Pathogenesis During Bartonellosis
Diseases of people with the acute form of Carrion’s disease, known as Oroya fever, are associated with the bites of several mosquito species. When a mosquito is bitten, Bartonella and insect saliva directly penetrate the bloodstream, attack and invade the red blood cells and spread by hematogenous followed by colonization of the endothelium cells of the vascular system, lymph nodes, tears and other organs. At the same time, up to 90% of red blood cells are hemolyzed, which causes severe anemia and the clinical picture of the disease.
It is believed that the manifestations of the disease reflect the overall immune status of the microorganism. Persons with impaired immune status develop Oroya fever. Penetrating into the bloodstream, numerous bartonella stick together with erythrocytes, penetrate into the endothelial cells of the capillaries and lymphatic vessels, where they multiply. The subsequent introduction of pathogens into erythrocytes and reproduction in them leads to phagocytosis and their destruction in the liver and spleen. The life span of red blood cells is shortened significantly, which leads to the development of anemia. This condition is exacerbated by a violation of erythropoiesis, occurring already in the early stages of the disease. The pathogenesis of hemolytic anemia is not installed. Agglutinins and hemolysins were not detected, and tests for the mechanical fragility of red blood cells give contradictory results. The introduction of the pathogen into the endothelial cells of the capillaries and the edema that develops in response to this leads to occlusion of the vessels and tissue infarctions. It is possible that damage to the reticuloendothelial function, which develops a second time as a result of massive phagocytosis of erythrocytes, is the cause of a significant frequency of excretion in Oroya fever of Salmonella and other intestinal bacteria.
As immunity develops, the pathogen is almost completely eliminated from the peripheral blood and the capillary endothelium. After the latent period, Bartonella is again found in the skin and subcutaneous tissues, where, undoubtedly, they are the main cause of the development of hemangioid foci of Peruvian wart disease. Recurrences of Carrion’s disease are rare, and if they develop, it is almost invariable in the form of warts.
Symptoms of Bartonellosis
The incubation period lasts 15 to 40 days, that is, usually about 3 weeks, but can take up to 3 to 4 months.
In typical cases, the disease is biphasic. In the first, acute phase, called Oroya fever, the body temperature rises to 39 – 40 ° C and remains at this level for 10 – 30 days, then slowly decreases. Fever is accompanied by pronounced symptoms of intoxication, chills, pouring sweat. There are severe headache, bone, joint and muscle pain, general malaise, insomnia, delirium or apathy, loss of appetite, nausea, vomiting. Hemorrhages appear on the skin, the liver and spleen are enlarged, jaundice is possible.
In severe disease, mortality in the acute stage of bartonellosis reaches 30%, with a favorable asymptomatic phase occurs, which in 3–6 months can turn into a skin rash (hillocks, spots, small light blotted nodules, subcutaneous nodes) called the Peruvian wart. The latter usually lasts 2 to 3 months.
Oroya fever is an acute infection manifested by generalized vasculitis, endocarditis and anemia with high mortality. The incubation period is 3 weeks; The disease begins suddenly with anorexia, headache, chills, and impairment of consciousness. Body temperature usually increases slightly, later joining myalgia and joint pain, shortness of breath, chest pain and insomnia. The development of severe anemia and various complications is typical. Asymptomatic forms are possible.
Peruvian wart is a chronic disease with granulomatous skin rashes (polymorphic red-purple, hard knots, sometimes resembling Kaposi’s sarcoma, formed by capillary growths and sometimes containing the pathogen). It appears after a long latency period or an attack of Oroya fever. More often observed education on the skin, but they can appear on the mucous membranes and exist from 1-2 months to several years.
Diagnosis of Bartonellosis
- Isolation of the pathogen.
- Biopsy followed by microscopy of biopsy material (tissue of skin nodules, lymph nodes or internal organs) impregnated with silver.
- Serological methods.
Etiotropic therapy of bartonellosis includes antibiotics: chloramphenicol 0.5 g 3-4 times a day; streptomycin intramuscularly at 0.5-1.0 g per day; tetracyclines (natural or semi-synthetic) 0.2 g 4 times a day.
In the acute phase of bartonellosis, Novarsenol is highly effective intravenously at 0.3-0.45 g once every 3-4 days. In recent years, with this disease, fluoroquinolones are prescribed more and more often: tarvide or cyprobay 200 mg 2 times a day intravenously (3-5 days), followed by switching to oral administration (7-10 days). They also conduct active detoxification and anti-anemic (including blood transfusion) therapy, prescribe hepatoprotectors, high doses of vitamins E, C, B12, folic acid, antihypoxants and macroerg precursors (cytochrome C, cyto-MAA, etc.).
External treatment does not play a significant role in bartonellosis. When attaching a secondary infection, antiseptics, ointments with antibiotics can be used, to accelerate the healing of ulcers, erosions – reparants, proteolytic enzymes.
Prevention of Bartonellosis
Destruction of mosquitoes in an endemic area. As a personal preventive measure, the protection of premises against the flight of mosquitoes and protection from their bites with the help of repellents are necessary. Immunoprophylaxis measures are not developed.