Caracterización y evolución temporal de la mortalidad por zoonosis bajo declaración obligatoria, entre los años 1997 y 2018 / Characterization and temporal evolution of mortality due to zoonoses under mandatory declaration, between the years 1997 and 2018

INTRODUCCIÓN: Las zoonosis son enfermedades transmitidas desde un hospedador animal al ser humano o viceversa. En Chile, las zoonosis de Notificación Obligatoria (NO) son: brucelosis, carbunco, triquinosis, hidatidosis, leptospirosis, dengue, enfermedad de Chagas, hantavirosis y rabia. OBJETIVO: Evaluar la tendencia y caracterizar la mortalidad por zoonosis de NO en Chile entre 1997-2018. METODOLOGÍA: Estudio ecológico de la mortalidad por zoonosis de NO. Se utilizaron bases de mortalidad y población oficiales. Se describió la mortalidad relativa, general y específica, según variables sociodemográficas. Se calcularon tasas de mortalidad anuales brutas (TMb) y ajustadas (TMa, método directo). Se evaluó la tendencia temporal con modelos de regresión de Prais-Winsten. Resultados: Entre 1997 y 2018 la mortalidad por zoonosis de NO correspondió al 0,12% (2.359 muertes) de la mortalidad total, siendo las principales causas la enfermedad de Chagas (59,8%), hidatidosis (23,9%) y hantavirosis (13,8%). La TMa general disminuyó significativamente (B: -0,017; IC95%: -0,024; -0,009) al igual que hidatidosis (B: -0,011; IC95%: -0,013; -0,008), sólo hantavirosis mostró un aumento (no significativo). CONCLUSIÓN: La mortalidad por zoonosis de NO disminuyó durante el período estudiado; solo la hantavirosis mostró un aumento en su tendencia. Se sugiere enfocar estrategias para prevenir la transmisibilidad y mortalidad por hanta, así como mejorar el acceso a tratamiento para las otras zoonosis.

BACKGROUND: Zoonoses are diseases transmitted from an animal host to humans or vice versa. In Chile, the zoonoses of mandatory notification are brucellosis, anthrax, trichinosis, hydatidosis, leptospirosis, dengue, Chagas disease, hantavirosis and rabies. AIM: To assess the trend and characterize the mortality from zoonoses of mandatory notification in Chile between 1997-2018. METHODS: An official mortality and population data were used. Relative, general and specific mortality rates were described according to sociodemographic variables. Crude and adjusted annual mortality rates (direct method) were calculated. Temporal trend was evaluated with the Prais-Winsten regression model. RESULTS: Between 1997 and 2018, the mortality rate due to zoonosis of mandatory notification corresponded to 0.13% (2152 deaths) of the total mortality, being Chagas disease (59.2%), hydatidosis (24.6%) and hantavirosis (13.5%) the main causes. The general adjusted mortality rate decreased significantly (B: -0.017; IC95%: -0.024; -0.009) as did hydatidosis (B: -0.011; IC95%: -0.013; -0.008), and only hantavirosis showed an increase trend (not significant). CONCLUSION: Mortality due to zoonoses decreased during the period; only hantavirosis showed an increasing trend. It is suggested to focus on strategies to prevent contagion and mortality by hantavirosis, as well as to improve access to treatment for the other zoonoses.

Epidemiology of human trichinellosis in Vojvodina province, Serbia, from 2005 to 2016.

Trichinellosis is one of the most important foodborne diseases in the Eastern European countries. The main objective of this study was to investigate the epidemiological patterns of trichinellosis outbreaks that occurred between 2005 and 2016 in Vojvodina, a northern province of the Republic of Serbia. The average incidence was 3.5 per 100,000 inhabitants. A total of 828 people acquired the infection. The disease occurred in all age groups, slightly more often in males, and quite frequently in a severe form considering the high share of hospitalised patients and the fatal outcome rate (41.6 ± 31.1% and 0.4%, respectively). Trichinella spiralis was confirmed as the causative agent in eight outbreaks. The outbreaks usually occurred among family members due to the consumption of pork or traditional pork products from not tested backyard pigs. Veterinary control measures and the education of consumers and farmers should be implemented to control this zoonotic disease.

Trichinella infection in Serbia in the first decade of the twenty-first century.

In Serbia, infection with Trichinella spp. has been recognized as a human health and animal husbandry problem for almost a century. The rate of swine infection gradually decreased from 0.14% to 0.02% between 2001 and 2010. For the past 5 years, Trichinella infections among swine were detected at levels higher than 0.05% in 3 districts of Serbia while prevalence persisted at lower levels for the rest of the country. During this 10-year period, there were 2257 cases of human trichinellosis, including 3 deaths; however, a significant decrease in the number of cases was reported during the last 5 years (fewer than 200 cases per year). The fact that prevalence data presented here are similar to prevalence data from 1990 indicates that this period of 10 years was needed to overcome the re-emergence of Trichinella infection in swine and humans that occurred during the last decade of the previous century.

Reviews on trichinellosis (I): renal involvement.

Besides cardiac and neurological complications of trichinellosis, renal involvement is the most important as regards the cases published and discussed in literature and is generally characteristic of the severe forms of the disease. This article focuses exclusively on the renal disturbances that may occur in this parasitic illness and includes a synopsis of published cases. Our primary goal was to increase the awareness of infectious diseases specialists, nephrologists, and general practitioners about these complications with possible fatal outcome. To our knowledge, this is the first international review dedicated to this topic. Cases for which enough details were available have been analyzed, and the results indicated that the mean age of the affected patients was 31.6 years, with a slightly male predominance (56.2%). The fatality rate was 26.1%. Proteinuria was detected in 84.8% of cases, hematuria in 30.4%, and casts were observed in urine specimens from 23.9% of patients. Renal failure was evidenced in 8.7% of patients, whereas renal lesions were found by biopsy or necropsy in 43.5% of cases. Of the routine laboratory parameters that are relevant for trichinellosis, mean eosinophil count was 32.2% and mean leukocyte count was 17,312 cells/µL. Finally, we emphasize on the necessity of establishing an early and correct diagnosis of trichinellosis to avoid later and severe complications. Additionally, implementation of public health and food safety prophylactic measures against the disease must represent an immediate priority for the affected regions.

Reviews on trichinellosis (II): neurological involvement.

Neurological involvement may occur in 0.2%-52% of cases with trichinellosis, generally in the most severely affected patients. This review focuses on neurotrichinellosis and includes a brief overview of selected cases reported in the literature. Our primary goal was to increase the awareness of infectious diseases specialists, neurologists, and general practitioners about these major complications with possible fatal outcome. Seventy seven of the cases, for which enough details were available, have been pooled for statistical analysis. The mean age of the investigated group was 34.6 ± 16.8 years. Patients with both focal and diffuse manifestations predominated (55.8%), and they were significantly older (40 ± 15.5 years old) than those who presented solely focal (28.9 ± 17.8 years old; p = 0.03) or diffuse lesions (27.9 ± 15.3 years old; p = 0.007). In most of the cases (59.7%), complete recovery was reported, whereas 23.4% of cases had sequelae and 16.9% of the patients died. Patients who died had significantly lower eosinophil counts (13.8% ± 14%) when compared with those who made complete recovery (28.7% ± 18%; p = 0.015) and the cases with sequelae (35% ± 17.9%; p = 0.006). To sum up, trichinellosis must be considered in the differential diagnosis of any patient with encephalitis or other central nervous system malady of ambiguous etiology.

The epidemiology of human trichinellosis in China during 1964-1999.

The large foci of trichinellosis are mainly located in the southeastern, the central and northeastern China. By the end of 1999, human cases with trichinellosis have been recorded in 17 out of 34 Provinces/Autonomous Regions/Municipals (P/A/M) of China. The seroepidemiological surveys of T. spiralis infection in humans were carried out in nine out of 34 P/A/M. The overall seroprevalence was 5.3%. The prevalence detected by muscle biopsy in Henan province was 2.5%. From 1964 to 1999, 548 outbreaks of trichinellosis, with 23,004 cases and 236 deaths, were recorded in 12 P/A/M of China. Pork is the predominant source of outbreaks of human trichinellosis in China, 525 (95.8%) out of 548 outbreaks were caused by eating pork. However, 14 outbreaks resulting from the consumption of mutton and game meat occurred in recent years, suggesting the increasing significance of herbivorous and wild animals as source for human trichinellosis.

Anaphylactic response to parasite antigens: IgE and IgG1 independently induce death in Trichinella-infected mice.

The response of animals infected with different Trichinella species (T. spiralis, T. britovi, T. pseudospiralis) to antigens of different Trichinella species was evaluated in outbred mice (CD1) and inbred mice (BALB/c, C3H, SJL, C57BL/6). In mice deficient for IgE or IgG1, T. spiralis only was used. In homologous conditions (i. e., same Trichinella species for antigens and infectious agent) mortality was very high (up to 100% in SJL and C57BL/6). The anaphylactic response in heterologous conditions was much lower and death was observed only in C57BL/6 and SJL mice. Experiments with deficient mice have shown that both specific IgE and IgG1 independently induce a fatal anaphylactic response.

Isolation and characterization of Trichinella pseudospiralis Garkavi, 1972 from a black vulture (Coragyps atratus).

A nematode from the genus Trichinella was observed in histological sections of breast and tracheal muscles from a black vulture Coragyps atratus from Alabama. Larvae obtained from breast muscle tissue that had been refrigerated for 8 days were infectious for laboratory mice. No nurse cell was observed around larvae in the black vulture or in experimentally infected mice examined 7 or 9 wk postinoculation. The identity of the parasite as Trichinella pseudospiralis was confirmed by DNA hybridization using the species-specific probe, pTsp 5.32. Infectivity trials showed that this isolate was also infective for pigs and chickens. This is the first report of isolation and transmission of T. pseudospiralis from an animal from North America.

[The effect of toluene and ammonia on the invasive process and immunological indices in experimental trichinelliasis in mice]. / Vliianie toluola i ammiaka na invazionnyi protsess i immunologicheskie pokazateli pri éksperimental'nom trikhinelleze u myshei.

Rap mice were exposed to toluene (T) inhalation for 10 days before invasion with 20 Trichinella spiralis larvae per g body weight (moderate infection). This resulted in diminished number of intestinal parasites in the presence of greater number of mast cells in the peritoneal exudate, higher IgE production, enhanced cell adhesion to trichinella larvae and of migration of splenic lymphocytes. Simultaneous inhalation of T and ammonia diminished the immune stimulating effect of the former. The number of intestinal trichinella was 1.5 times more but still twice less than in controls. Inhalation of T during the first 10 days of infection stimulated the immune response only in mice given 5 larvae per g. In those given 20 or 60 larvae per g, the immune response was suppressed and 40 and 100% of mice perished respectively. The exposure to T during 30-39 days of infection of mice given 35 larvae per g (the intensive infection) resulted in 50% death of the animals without significant changes in immune response. Simultaneous therapy with mebendazole (75 mg/kg) provided 100% survival in the presence of suppressed immune response. 100% of mice of the same group not exposed to T but treated with mebendazole died. The toxic and immunomodulating effects of T differ in intact and infected mice due to the dense, the stage of infection and to chemotherapy.

[The epidemiological profile of trichinosis in the state of Zacatecas]. / Perfil epidemiológico de la triquinosis en el estado de Zacatecas.

A compilation of data from the cases which have occurred in Zacatecas during the period between 1976 and 1987 has been made. It describes the endemia and locates the problem in time, person and space. Because of their impact, magnitude and consequences the more important data of the outbreaks is presented. The first case of trichinosis diagnosed in Zacatecas was in 1975; since then there have been other outbreaks; four in 1978, with the highest mortality of 33 per cent which occurred in Laguna del Carretero a community of Villanueva. During the period between 1979-1988 there have been 17 more, among these a death occurred in Valparaiso and, in Pozo de Gamboa there was an abortion in a 20-year-old female patient. This infection has higher frequency in urban areas. The most affected group age is 15-44 years; in this group there have been 51 percent of the cases occurring in females in a proportion of 1:1.8. Seven of the 36 countries in the state of Zacatecas, such as Zacatecas, Villanueva, Valparaiso, Panuco, Jerez, Jalpa and Guadalupe, have reported cases; the countries are listed by frequency. The transmission in most of the cases was caused by ingestion of raw pork products, in a fen undercooked pork meat. The diagnosis was confirmed in sixty cases by the conservation of the parasite in muscle biopsy and oronyosistis which represent a 38 percent of the reported total cases. Six cases was confirmed by histologic sections and immunoelectrophoresis test.

[Case of trichinosis with lethal outcome due to consumption of brown bear meat in the Krasnoyarsk Territory]. / Sluchai trikhinelleza so smertel'nym iskhodom pri upotreblenii v pishchu miasa burogo medvedia v Krasnoiarskom krae.

One autopsy case of trichinellosis (in a man of 22) with extensive involvement of the locomotor apparatus (secondary infectious-allergic polymyositis) is presented. Group infection with trichinellosis occurred by eating of insufficiently treated meat of a brown bear which confirms the existence of a natural focus of trichinellosis in the Krasnoyarsky kray.