Epidemiology of hemorrhagic fever with renal syndrome in the north Volga-Viatka region

The results of the ecological and epidemiological study of hemorrhagic fever with the renal syndrome (HFRS) in the Kirov region for the period of 1987-2000 are presented. HFRS morbidity rate varied from 1.3 to 13.7 per 100,000 population, which corresponded to the figures registered in the Volga Vyatka region. Cases of HRFS were mainly (90%) registered in three southern districts of the region. The moderate degree of correlation between morbidity rate and the number of wild mammals (r = 0.55) was established. Periodic morbidity rise occurred every 3 years. In 1998-2000 the contamination of wild mammals with HFRS virus increased and reached 7.6-9.5%. Infection factors connected with everyday human activities somewhat prevailed, industrial and agricultural types of infection constituting 43.8%. Males aged 20-49 years prevailed among the patients. Morbidity rate among urban dwellers exceeded that among town residents.     

Morbidity and mortality in acute viral hepatitides in a hyperendemic region. The role of viral hepatitis E

Official annual statistical data on morbidity in acute viral hepatitides (AVH), including the number of lethal cases, for 1985-1995 were analyzed. Mortality rates per 100,000 of the population at the period of 11 years were calculated for different age groups, sex and the place of residence. 396 and 99 patients were examined for the presence of serological markers of hepatitides A, B and E, respectively, at the periods of epidemic rises in morbidity and satisfactory epidemic situation. In the course of 11 years AVH caused the death of 22,405 persons. In 1985-1987 the average mortality level (ML) reached 12.3-17.8 per 100,000 of the population (with morbidity being 1,200-1,400 and was essentially higher among the rural population in comparison with the urban population. During these years the highest ML, was registered among children aged 0-2 years (190-50 per 100,000) and, among adults, mainly among women aged 20-29 years (21.4-19.6 per 100,000). During the years when the epidemic of AVH was absent, ML among these groups was essentially lower: 40-20 among children aged 0-2 years and 4-5 among women aged 20-29 years. In 1987 in the Fergana Valley hepatitis E was detected in 72.2% of all examined patients, and in the southern areas of the country in 68.7%. A sharp rise on mortality among women of the productive age at the period of the epidemic rise of AVH morbidity in the endemic region indicated that this epidemic was linked with hepatitis E. High ML among young children may be indicative of a highly unfavorable course of hepatitis E in the group of infants, which had never been registered before. This newly established regularity may be used for the retrospective diagnostics of the outbreak of hepatitis E.     

Epidemic process of pertussis in Moscow

Materials reflecting the dynamics of pertussis morbidity during the period of 1958 - 2003 under the conditions of prolonged mass immunization of the child population with adsorbed DPT vaccine are presented. The planned vaccination of children led to the decrease of pertussis morbidity during the first 10 years, but groundless abstentions from vaccination during the 1980s - 1990s contributed to a sharp rise in morbidity among children of younger age groups. During the recent four years a rise in pertussis morbidity was registered in 2000 (71.79 per 100,000 of the population), followed by the most significant for the last 20 years drop in morbidity in 2002--down to 9.89. But in 2003 the growth of morbidity was again registered (38.67). Recently periodic rises and drops in morbidity occurred simultaneously with the increased coverage of children of younger age groups with vaccination. In recent years changes in the age structure of patients were observed: the specific proportion of school children increased (in 2003 morbidity rates in children aged 6 - 10 years were 288.6 - 270.7), simultaneously high morbidity among children aged up to one year (274.9) was registered. The specific proportion of pertussis-affected children aged above 7 years reached 65%. From the late 1990s until present in 87.1% of cases strains of serotype 1.0.3 prevailed in the population of B. pertussis strains. But in recent years the circulation of strains 1.2.3, spread in the prevaccination period and having toxicity similar to that of strains of serotype 1.0.3, while exceeding them in virulence, in sufficiently high proportion (7.0% in 2002) was noted. This was indicative of the possibility of the unfavorable development of the epidemic process of pertussis infection.     

Epidemiological pattern of scarlet fever in recent years

During the period of 1953-2001 scarlet fever morbidity level fluctuated from 670.3 to 65.9 per 100,000 of the population in Moscow and from 531.9 to 35.0 per 100,000 of the population of the Russian Federation. In recent years an increased morbidity was more pronounced in Moscow than in the Russian Federation as a whole. Children formed the greater part of scarlet fever patients, the cases of scarlet fever among children in Moscow occurring more often than, on the average, in Russia. As before, annual morbidity among children attending children's institutions was higher 3- to 4-fold than among children brought up at home. This difference was most sharply pronounced among young children during the first two years of their life. In contrast to morbidity observed during previous 20-30 years, a drop in morbidity among children during the first two years of their life was registered, while morbidity level among children aged 3-6 years and 7-14 years increased. Scarlet fever morbidity had a pronounced seasonal (autumn-winter) pattern. In a group of children aged 3-5 years who attended organized groups, on the average, 78.6% of scarlet fever cases fell on seasonal morbidity, the most prolonged one.     

Diphtheria morbidity in Russia today

The data on diphtheria morbidity and the occurrence of carrier state for its causative agent at the period of 2001-2002 were analyzed. The rates of morbidity and detected carrier state for these years were 0.63-0.55 and 0.65-0.64 respectively. Nevertheless, in spite of the relatively low morbidity rates the presence of the toxic forms of diphtheria (400 patients for two years) and lethal cases (with lethality rate reaching 5.4%) indicated that the epidemic situation in diphtheria remained tense. The most unfavorable situation was observed in the North-Western and Central regions of Russia. In urban areas morbidity rates were still 2- to 3-fold higher in than in rural ones, but the latter showed a higher percentage of severe cases (46.6% in 2001 and 39.7% in 2002) and lethal outcomes (13.6% and 19.2%). The latter was indicative of drawbacks in the immunoprophylaxis, diagnostics and treatment of diphtheria in rural areas. In the total structure of diphtheria patients adults prevailed: 75%. The highest morbidity rates were registered among children aged 3-6 years, among adults in the age groups of 18-19 years and 50-59 years. The epidemic process developed mainly among the immunized population, which was indicated by a high proportion of vaccinated persons among those affected by this infection (62.8-66.6%) and a mild course of the disease in the majority of them. The present epidemiological situation in diphtheria was determined by patients not vaccinated against this infection. The proportion of severe cases among nonvaccinated children was 42.4-51.6% and lethal outcomes, 12.9-15.1%. Among nonimmunized adults these figures were equal to 43.1% and 9.3% respectively. The highest percentage of children, not vaccinated during the first years of their life, was registered among those in the asocial families, refugees and homeless persons. Among adults these were persons above 50 years old, as well as jobless persons of working age, pensioners and invalids, who had limited possibilities of undergoing vaccination due to their social position. It was these social and age groups that should be regarded as risk groups with respect to the severity of the course of diphtheria and lethality. To stabilize diphtheria morbidity, the full complex of prophylactic and antiepidemic measures, and primarily the immunization of the population, should be systematically carried out.     

Morbidity and prophylaxis of hemorrhagic fever with renal syndrome in the Republic of Bashkortostan

The brief retrospective analysis of morbidity, epizootological data and preventive measures with respect to haemorrhagic fever with renal syndrome (HFRS) during the whole period of its registration on the territory of the Republic of Bashkortostan along with the structure of HFRS morbidity during epidemic seasons of 1998 and 1999 is presented. The main causes of decreased HFRS morbidity in 1998, its rise in 1999 as well as prognosis for the year 2000 were detected. The level of HFRS morbidity among the population was found to be directly related to the number of rodents and their infection rate. The basic strategy of epidemic control interventions has been proposed.     

The manifestations of an epidemic process of typhoid infection in Moscow

The work deals with the results of typhoid morbidity in Moscow for the period of 1980-1988. The morbidity rate varied from 0.98 to 0.17 cases per 100,000 of population with a tendency towards decrease. In the structure of morbidity local cases accounted for 46.8% and cases of infection contacted outside Moscow accounted for 53.2%. The morbidity level was low throughout the whole territory, only in two districts morbidity rate was significantly higher (P = 95%) than the average morbidity rate in the whole of the city. In the group of local cases morbidity had no pronounced seasonal character, in contrast to cases due to infection contacted outside the city which were mostly registered in summer and autumn. Persons aged 21-30 years were found to be the most affected age group. The general factors, and not the contact route, are supposed to play the main role in the realization of the mechanism of infection transfer. Under modern conditions, some manifestations of the epidemic process of typhoid infection can be detected only at the level of the whole city, or even the whole country.     

Hepatitis A in Estonia (1990-1999)

During recent 10 years (1990-1999) essential changes occurred the epidemiology of viral hepatitis A (VHA) in Estonia: simultaneously with a decreased level of morbidity (morbidity rate per 100,000 of the population was 78.4 in 1990 and 7.7 in 1996, or 1,241 and 112 cases, respectively), a shift in the age structure of patients from children of preschool age to older age groups took place. Everyday contacts were the main established route of VHA transmission in recent years, but in more than 80% of cases the risk factors of the virus transmission remained obscure. During the regional outbreak of VHA in North Estonia in 1998 (937 out of 989 cases registered in the country) a rise in morbidity was observed among young people aged 15-29 years, when a wide spread of parenteral viral hepatitides B and C and drug addiction were registered in this region. During this outbreak VHA was transmitted mainly through everyday contacts. Still the considerable prevalence of injection drug users who practiced the group use of syringes and needles and took drugs from common containers, a sufficiently high level of the mixed forms of the disease (more than 18% of all registered cases of VHA), detected for the first time, make it possible to suggest that the parenteral transmission route could appear among persons belonging to the above mentioned group. Vaccination is regarded as the most effective measure for the prophylaxis of VHA.     

Activation of natural tularemia foci of the field-meadow and steppe types on the territory of Tula Province 1977-1978

Natural tularemia foci of the meadow and steppe type are extremely stable and become active in those years when the most favourable living conditions for rodents appear. For the first time during the last 30 years a great increase in the number of common voles, accompanied by widely spread epizooty covering the whole territory of the Tula region, was observed. House mice, common field mice, harvest mice and black rats were also involved in this epizooty and 235 tularemia patients with all clinical forms of the disease were registered, the pulmonary form of the disease being prevalent. The cases of the disease were observed among both urban and rural population. In spite of a high morbidity rate, no cases of group infection were registered in domestic conditions and among agricultural workers due to the existence of the numerous immune layer among the population. The formation of this layer resulted from planned vaccinal prophylaxis covering, on the average, 86.3% of the rural population of the region.     

The intensity of the immune response to the hemorrhagic fever with renal syndrome virus among different population groups of Bashkortostan]

For the first time the natural immune stratum to hemorrhagic fever with the renal syndrome (HFRS) among the population of all regions of Bashkiria, a large territory with the highest morbidity level in this infection in the USSR, was studied. 9,176 persons over 15 years of age were examined by radioimmune techniques. Analysis of the immune structure of the population revealed that the share of immune males was higher than that of immune females, but the difference was less than the difference between males and females among the registered HFRS patients. Among children immune persons were almost completely absent. The immune stratum increased rather slowly among persons under 40 years, and only from this age the considerable increase of the immune stratum was observed (up to 16.2%). High risk groups included persons of such professions as forestry workers, truck and tractor drivers, oil workers and prospectors, livestock breeders, builders. These data may be used for the formation of groups to be vaccinated against HFRS in foci with different degrees of activity. Before vaccination the correction of groups to be vaccinated in a given region should be carried out, taking into account the immune structure of the population and the specific features of the local landscape and economy.     

Prevention and control of HIV infection in the Osh region of the Kyrgyz Republic

A total of 178 cases of HIV infection were diagnosed in the Osh region of the Kyrgyz Republic for January 1, 2003, the intensity of the prevalence of HIV infection being 14.5 per 100,000 of the population with this figure for the whole republic being equal to 5.9. In the dynamics of the HIV infection epidemic two periods were detected. During the first 3 years (1998-2000) a few individual imported cases of HIV infection were registered in the region. During the last 2 years (2001-2002) 98.8% of all cases of HIV infection registered in the region, as well as the presence of an epidemic outbreak among injection drug users (IDU), were detected. The risk factors of getting HIV infection were the intravenous use of drugs and a low level of information among young people concerning the routes of transmission of this infection and means of protection from HIV/AIDS: the promotion of healthy life style among young people, the introduction of the programs of "harm reduction" among IDU and the rules of safe sex.     

Viral hepatitis in different population groups of Republic of Sakha (Iakutia)

A survey for the presence of markers of viral hepatitis B, delta, C and E among different groups of the population of the arctic and agricultural zones of the Republic of Sakha (Yakutia), as well as in Yakutsk, was carried out. The survey revealed that viral hepatitides with the parenteral mechanism of the transmission of infective agents were widely spread among the population. In the arctic zone HBsAg was detected in persons aged 20 years and older in 10.8-17.1% of cases. On the average, in the arctic zone antibodies to virus delta were detected in 2.4% of cases. In different regions of the agricultural zone the detection rate of HBsAg was also high (10.4-23.8%). In the Namsk and Vilyui regions delta infection was registered among adolescents (15-19 years of age) in 8.7 and 22.4% of cases respectively. In the Mountainous region anti-delta antibodies were detected among persons aged 20 years and older in 31% of cases. The survey showed the presence of considerable differences in the detection rate of the markers of hepatitis B, depending on the ethnic origin of the examined patients. Similar tendencies were found to exist with respect to delta infection.     

Epidemiology of bacillary dysentery in Algeria. I. The epidemiological aspects of dysentery in Algeria

Bacterial dysentery plays an important role among infectious diseases in Algeria. A tendency to the growth of the morbidity rate has been observed. Dysentery is irregularly spread in different zones of the country. The highest morbidity rate is registered in the Sahara zone and in the eastern part of the country. The morbidity rate among the urban population is higher than among the rural population. S. flexneri prevail in the etiological structure of dysentery infection. Of all age groups, the highest morbidity rate is observed among children during the first 2 years of life. In recent years lethality varies between 2.9% and 7.5%. Patients are hospitalized mainly on the basis of clinical symptoms.     

Spread of salmonellosis in Moscow and the ways of its prophylaxis

The article deals with the results of the epidemiological analysis of the spread of salmonellosis in Moscow. During the last 15 years the proportion of Salmonella enteritidis was about 80% and more. After salmonellosis morbidity decreased to 19.9 per 100,000 of the population (the minimum level) in 1985 its sharp rise was noted. Morbidity rate increased from 31.7 in 1987 to 55.1 per 100,000 in 1988, then to 93.9 per 100,000 of the population in 1989 (the maximum level). In the subsequent years up to 1996 a decrease in morbidity rate was observed, but in 1997-2002 morbidity rate stabilized within 29.8-35.7 per 100,000 of the population without a perceptible tendency towards decrease. The sharp increase of the etiological role of S. enteritidis which led to a wide spread of Salmonella infections was caused by the "chicken-egg" factor of their transmission. High morbidity rate among children and adults, registered all the year round, is the consequence of the constant epidemic activity of this factor.     

Epidemiological and immunological monitoring of tetanus in Georgia (Republic)

During the period of 1961-1990 the regular immunological and epidemiological monitoring of tetanus was carried out. At the prevaccination period (1937-1960) 140 cases of tetanus were registered, 77 patients died (morbidity rate being 0.97-0.11 per 100,000 of the population with mortality rate equal to 55.6%). At the period of mass vaccinal prophylaxis (1960-1990) 56 cases were registered and 27 patients died (the corresponding values: 0.09-0.11 with 48.2% mortality). In 1981-1990 altogether 53,213 vaccinees were examined. 4,864 vaccinees (8.9%) proved to be seronegative and 43,615 vaccinees (81.9%) were found to have protective antibody titers. 4,220 pregnant women were examined; 476 women (11.2%) proved to be seronegative and 3,576 women (84.3%) were found to have protective antibody titers. Timely specific prophylaxis proved to be the only way for decreasing tetanus morbidity.     

Cancer pattern and survival in a rural district in South India

Background: Cancer pattern data are rare and survival data are none from rural districts of India. Methods: The Dindigul Ambilikkai Cancer Registry (DACR) covering rural population of 2 millions in Dindigul district, Tamil Nadu state, South India, registered 4516 incident cancers during 2003–2006 by active case finding from 102 data sources for studying incidence pattern, of which, 1045 incident cancers registered in 2003 were followed up for estimating survival. House visits were undertaken annually for each registered case for data completion. Cancer pattern was described using average annual incidence rates and survival experience was expressed by computing observed survival by actuarial method and age-standardized relative survival (ASRS). Results: The average annual age-standardized rate per 100,000 of all cancers together was higher among women (62.6) than men (51.9) in DACR. The most common cancers among men were stomach (5.6), mouth (4.2) and esophagus (3.7). Cervical cancer (22.1) was ranked at the top among women followed by breast (10.9) and ovary (3.3). DACR incidence rates were lesser by at least two folds and 5-year survival were on par or lower than Chennai metropolitan registry for most cancers. Five-year age-standardized relative survival (%) in DACR was as follows: all cancers (29%), larynx (48), mouth (42), breast/tongue (38) and cervix (37). Conclusion: Cancer incidence was significantly lower, cancer patterns were markedly different and population-based cancer survival was lower in rural areas than urban areas thus providing valuable leads in estimating realistic cancer burden and instituting cancer control programs in India.     

The etiological structure of acute bacterial meningitis in different regions]

In 1985-1989 the etiological structure of acute bacterial meningitides (ABM) in children was studied in 4 largest industrial cities in different regions of the European part of the former USSR, as well as in 2 industrial cities of western Siberia. Due to the common methodological approach used in all investigations, comparable data were obtained in all cities. These investigations revealed that meningococci caused 53.0-86.7% of all cases of ABM in children, which corresponded to moderately increased morbidity rate in meningococcal infection (3.9-11.0 cases per 100,000 of the population, mostly 5.0-7.0 cases) in these cities with its progressive decrease during 3-4 years of observation. The gradual change of meningococci from group A, prevailing in the '70s and early '80s, to group B and in some cases the appearance of group C meningococci, accompanied by a decrease in morbidity rate, were noted. In St. Petersburg the indices of ABM morbidity in children aged up to 5 years for 1987 and 1988, caused by Haemophilus influenzae (0.74 and 4.13) and pneumococci (3.23 and 4.86), could be calculated. A great number of ABM cases of unclear etiology (15.9-33.3%) suggests that the number of ABM cases caused by these two infective agents was underestimated.     

Population-based incidence of typhoid fever in an urban informal settlement and a rural area in Kenya: implications for typhoid vaccine use in Africa

Background

High rates of typhoid fever in children in urban settings in Asia have led to focus on childhood immunization in Asian cities, but not in Africa, where data, mostly from rural areas, have shown low disease incidence. We set out to compare incidence of typhoid fever in a densely populated urban slum and a rural community in Kenya, hypothesizing higher rates in the urban area, given crowding and suboptimal access to safe water, sanitation and hygiene.

Methods

During 2007-9, we conducted population-based surveillance in Kibera, an urban informal settlement in Nairobi, and in Lwak, a rural area in western Kenya. Participants had free access to study clinics; field workers visited their homes biweekly to collect information about acute illnesses. In clinic, blood cultures were processed from patients with fever or pneumonia. Crude and adjusted incidence rates were calculated.

Results

In the urban site, the overall crude incidence of Salmonella enterica serovar Typhi (S. Typhi) bacteremia was 247 cases per 100,000 person-years of observation (pyo) with highest rates in children 5–9 years old (596 per 100,000 pyo) and 2–4 years old (521 per 100,000 pyo). Crude overall incidence in Lwak was 29 cases per 100,000 pyo with low rates in children 2–4 and 5–9 years old (28 and 18 cases per 100,000 pyo, respectively). Adjusted incidence rates were highest in 2–4 year old urban children (2,243 per 100,000 pyo) which were >15-fold higher than rates in the rural site for the same age group. Nearly 75% of S. Typhi isolates were multi-drug resistant.

Conclusions

This systematic urban slum and rural comparison showed dramatically higher typhoid incidence among urban children <10 years old with rates similar to those from Asian urban slums. The findings have potential policy implications for use of typhoid vaccines in increasingly urban Africa.     

Cancer incidence in southern Iran, 1998-2002: results of population-based cancer registry

Purpose: The main aim of this study was to obtain population-based cancer incidence data for the entire population of Fars province in Iran, and to compare these rates with those obtained from a previous study in the same population ten years previously. Methods: Data were collected on all patients in major cities of Fars province who were diagnosed with cancer between 1998 and 2002. The data were computerized using SPSS (Chicago, IL) software, version 13.0, and MS EXCEL (Microsoft, Redmond, WA) software with Persian fonts. The results are presented as incidence rates of cases by site, sex, age, crude rates, and age-standardized rates per 100,000 person-years (ASRs), using the direct method of standardization to the world population. Results: During the 5-year study period, 8359 new cancer cases were registered. Diagnosis of cancer was based on histopathological criteria in 86.7%, clinical or radiological criteria in 9.4% and death certificate only in 3.9% of cases. According to the calculated ASRs, the 5 most frequent cancers in women were breast (13 per 100,000), stomach (4.4 per 100,000), lung and bronchus (2.9 per 100,000), uterus (2.7 per 100,000), and colon and rectum (2.6 per 100,000); and in men, the 5 most frequent types were stomach (9.2 per 100,000), bladder (6.8 per 100,000), lung and bronchus (6.3 per 100,000), lymphocytic leukemia (4.1 per 100,000), and skin melanoma (3.8 per 100,000). The ASR for all cancers in men was 64.5 per 100,000, and that for women was 55.5 per 100,000. Conclusion: Considering the limitations of this study, our results should be taken as the minimum incidence rates of cancers in Fars province, southern Iran. Significant differences were observed between the two study periods. However, we most likely have underestimated the frequencies of some tumors.     

Meningococcal infection in the Uzbek SSR

The epidemiological characteristics of meningococcal infection in Uzbekistan during the period of 8 years since its last epidemic rise in 1972 is presented. Differences in the intensity of the epidemic process among the urban and rural population due to a considerable isolation of most of the rural populated localities from the district centers and the low population density in the republic have been established. The seasonal distribution of the infection had a winter-spring character in urban areas and a spring character in rural areas. 63.4% of all cases were children under 14 years. In cities a high morbidity level among adolescents and young people was determined mainly by visitors from rural areas. A high epidemiological importance of healthy carriers, predominantly schoolchildren and young people was established. The immunological studies of humoral immunity in different groups of the population indicate that the process of immunization was more rapid in cities.