Date: Fri 21 Sep 2018
Source: Biobiochile [machine trans., edited]
The Ministry of Health confirmed that from June 2018 to date, 31 people have been infected with cholera in 3 different regions of the country. The microorganism has been present in Chile for some time, but the Undersecretary of Public Health, Paula Daza, told El Mercurio that "this year  what we have had is an outbreak, because we've had a larger number of cases in a short period of time."
According to data from the Regional Ministerial Secretariat (Seremi) of Health of the [Santiago] Metropolitan Region, of the total number of patients, 29 are in this region, with the municipality of La Florida leading the list with 4 infections. Other communes with reported cases are Huechuraba, Las Condes, Vitacura, La Reina, Penalolen, Puente Alto, La Cisterna, Pedro Aguirre Cerda, Santiago, Maipu, Central Station, Renca, Quinta Normal, Conchali, Independencia, Recoleta, and Providencia.
The list is magnified by other cases that occurred in the regions of Valparaiso and Atacama. Of the total number of patients registered so far, 19 are women, and 18 had a history of other underlying diseases.
The symptoms of the infection are similar to a prominent gastroenteritis. The Ministry of Health confirmed that currently no deaths have been recorded as a result of the infections, but 9 people had to be hospitalized.
As to which polluted irrigated waters were the trigger of the outbreak, the Health Seremi of the Metropolitan Region, Rosa Oyarce, assured the same media that "it was ruled out because all the necessary tests were done to the irrigation canals that go directly to the irrigations of the vegetables." Meanwhile, Deputy Secretary Paula Daza indicated that the cause of the outbreak cannot yet be determined. The health authority stressed that it has been ruled out that the bacterium came from abroad, because the ministry's information indicates that none of the patients took previous trips to other countries that could have caused the infection. [Byline: Felipe Diaz]
[In the previous post, 14 cases were reported; now that number has more than doubled. Chile had a toxigenic cholera outbreak that originated in neighboring Peru between 1991 and 1994, affecting approximately 150 persons.
It is not stated if this cluster of cases is related to a non-toxigenic O1 or O139 strain or a non-epidemic strain of non-O1, non-O139 _Vibrio cholerae_. As a review, the flagellar (H) antigens of _V. cholerae_ are shared with many water vibrios and therefore are of no use in distinguishing strains causing epidemic cholera. The O (somatic) antigens, however, do distinguish strains of _V. cholerae_ into 139 known serogroups. Almost all of these strains of _V. cholerae_ are non-virulent. Until the emergence of the Bengal (O139) strain (which is "non-O1"), a single serogroup, designated O1, has been responsible for epidemic cholera.
There are 3 distinct O1 serotypes -- Ogawa, Inaba, and Hikojima -- each of which may display the "classical" or El Tor phenotype (or biotype). The biotypes are distinguished by their expression of surface antigens A, B, and C. Ogawa contains antigens A and B; Inaba contains antigens A and C; and Hikojima contains antigens A, B, and C. The latter serotype is relatively rare.
In almost all cases, non-O1, non-O139 _V. cholerae_ isolates do not possess the genes for cholera toxin. Some isolates can cause substantial diarrhea (1-4). The type III secretion system (TTSS) is a mechanism for Gram-negative bacilli to introduce effector proteins into host cell cytoplasm (5). It has been reported that a functional TTSS is required for at least in some non-O1, non-O139 isolates to induce diarrhea in an animal model associated with small-bowel damage and production of proinflammatory cytokines (6). In addition, TTSS contributes to virulence even in the presence of cholera toxin and TCP (6).
2. Sharma C, Thungapathra M, Ghosh A, et al. Molecular analysis of non-O1, non-O139 _Vibrio cholerae_ associated with an unusual upsurge in the incidence of cholera-like disease in Calcutta, India. J Clin Microbiol. 1998; 36: 756-63; <http://jcm.asm.org/content/36/3/756.long
4. Chatterjee SC, Ghosh K, Raychoudhuri A, et al. Incidence, virulence factors, and clonality among clinical strains of non-O1, non-O139 _Vibrio cholerae_ isolates from hospitalized diarrheal patients in Kolkata, India. J Clin Microbiol. 2009; 47(4): 1087-95; <http://jcm.asm.org/content/47/4/1087.long
6. Shin OS, Tam VC, Suzuki M, et al. Type III secretion is essential for the rapidly fatal diarrheal disease caused by non-O1, non-O139 _Vibrio cholerae_. mBio 2011; 2(3): e00106-11; <http://mbio.asm.org/content/2/3/e00106-11.long
- ProMed Mod.LL]