What is Paratyphus A and B?
Paratyphoids A and B are acute infectious diseases with a fecal-oral transmission mechanism, similar in pathogenesis and main clinical manifestations to typhoid fever.
Causes of Paratyphus A and B
The pathogens, S. paratyphi A and S. paratyphi B, are Gram-negative motile sticks of the Salmonella genus of the family Enterobacteriaceae. Bacteria have O-Ar and H-Ar, but not Vi-Ar. Their morphological and cultural properties are basically the same as S. typhi, and when cultured material is sown on liquid nutrient media, they take into account the ability of paratyphoid microorganisms to form gas. The resistance of paratyphoid bacteria in the environment and under the influence of disinfectants does not differ from that of the causative agent of typhoid fever.
The reservoir of the causative agent of paratyphoid A – a sick person and bacteria carriers.
The reservoir of the causative agent of paratyphoid fever B – man and animals (cattle, pigs, poultry). A sick person usually secretes a pathogen from the first days of clinical manifestations and during periods of illness and convalescence (2-3 weeks). The carrier of paratyphoid bacteria is formed more often than typhoid.
The transmission mechanism is fecal-oral, the transmission routes are food, water, household. When paratyphoid A is dominated by water, with paratyphoid B – food (especially through milk).
The natural susceptibility of people is high. Post-infectious immunity is species-specific.
Major epidemiological signs. Paratyphoid B is widespread; paratyphoid A is less common, mainly in the countries of Southeast Asia and Africa. Diseases are recorded sporadically or in the form of limited outbreaks. The main manifestations of the epidemic process are the same as in typhoid fever.
Pathogenesis During Paratyphus A and B
The pathogenesis of the disease is similar to that of typhoid fever.
Symptoms of Paratyphus A and B
The symptoms of typhoid and paratyphoid are very similar. However, with paratyphoid A, the incubation period is shorter than with typhoid fever, averaging 6-10 days. Characteristic acute onset of the disease with a rapid rise in body temperature and the presence in the initial period of catarrhal phenomena – rhinitis, cough. The face of patients is hyperemic, the vessels of the sclera are injected, you can observe herpetic eruptions on the lips and wings of the nose. The temperature response is not as constant as in typhoid fever, often takes the wrong character, and its duration is less. At the height of the disease, chills and sweating are possible. Quite often, rash appears early (4-7th day of illness). In addition to the characteristic roseolus rash, it can be core-like or petechial. It is more abundant and is located not only on the skin of the abdomen and chest, but also on the limbs. Characteristic polymorphism of rash and “pouring” in the dynamics of the disease. Most often the disease occurs in moderate form, intoxication is moderately expressed, and its duration is less than with typhoid fever. Just like typhoid fever, the disease can take a relapsing course.
The incubation period for paratyphoid B is usually 5-10 days. The disease begins acutely; characteristic is the development of gastroenteritis with abdominal pain, nausea, vomiting, weakening of the stool and fever, which can be mistakenly interpreted as the beginning of food toxicoinfection. The temperature reaction is wrong and relatively short in time. Just as with paratyphoid A, a rash can be varied, abundant and located not only on the body, but also on the extremities. Most often the disease occurs in moderate form, however, there are cases of severe paratyphoid fever with the development of meningitis, meningoencephalitis and septicopyemia.
Diagnosis of Paratyphus A and B
Differential diagnosis is similar to that of typhoid fever. Considering the clinical features of the initial period of paratyphoid fever, they must be differentiated from salmonellosis, foodborne toxicoinfections (paratyphoid B), as well as from diseases accompanied by respiratory catarrhal phenomena (paratyphoid A).
Treatment of Paratyphus A and B
Treatment should be comprehensive, including care, diet, etiotropic and pathogenetic agents, and according to indications – immune and stimulating drugs. Bed rest is up to 6-7 days of normal temperature, from 7-8 days is allowed to sit, and from 10-11 to walk. Food digestible, gentle gastrointestinal tract.
In the period of fever, it is steamed or given in a shabby form (table N 4a). Among the drugs of specific action, chloramphenicol takes the leading place (0.5 g dosage 4 times a day) up to 10 days of normal temperature. To increase the effectiveness of etiotropic therapy, mainly with the aim of preventing recurrence and the formation of chronic bacterial secretion, it is recommended to be used in the process with agents that stimulate the body’s defenses and increase specific and nonspecific resistance (typhoid-paratyphoid B vaccine).
Prevention of Paratyphus A and B
Prevention comes down to general sanitary measures: improving the quality of water supply, sanitary cleaning of populated areas and sewage systems, fighting flies, etc.
Clinical supervision of patients with paratyphoid fever is carried out for 3 months.