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Dórea JG. Low-dose Thimerosal in pediatric vaccines: Adverse effects in perspective. ENVIRONMENTAL RESEARCH 2017; 152:280-293. [PMID: 27816865 DOI: 10.1016/j.envres.2016.10.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Vaccines are prophylactics used as the first line of intervention to prevent, control and eradicate infectious diseases. Young children (before the age of six months) are the demographic group most exposed to recommended/mandatory vaccines preserved with Thimerosal and its metabolite ethylmercury (EtHg). Particularly in the less-developed countries, newborns, neonates, and young children are exposed to EtHg because it is still in several of their pediatric vaccines and mothers are often immunized with Thimerosal-containing vaccines (TCVs) during pregnancy. While the immunogenic component of the product has undergone more rigorous testing, Thimerosal, known to have neurotoxic effects even at low doses, has not been scrutinized for the limit of tolerance alone or in combination with adjuvant-Al during immaturity or developmental periods (pregnant women, newborns, infants, and young children). Scientific evidence has shown the potential hazards of Thimerosal in experiments that modeled vaccine-EtHg concentrations. Observational population studies have revealed uncertainties related to neurological effects. However, consistently, they showed a link of EtHg with risk of certain neurodevelopment disorders, such as tic disorder, while clearly revealing the benefits of removing Thimerosal from children's vaccines (associated with immunological reactions) in developed countries. So far, only rich countries have benefited from withdrawing the risk of exposing young children to EtHg. Regarding Thimerosal administered to the very young, we have sufficient studies that characterize a state of uncertainty: the collective evidence strongly suggests that Thimerosal exposure is associated with adverse neurodevelopmental outcomes. It is claimed that the continued use of Thimerosal in the less-developed countries is due to the cost to change to another preservative, such as 2-phenoxyethanol. However, the estimated cost increase per child in the first year of life is lower than estimated lifetime cost of caring for a child with a neurodevelopmental disorder, such tic disorder. The evidence indicates that Thimerosal-free vaccine options should be made available in developing countries.
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Affiliation(s)
- José G Dórea
- Professor Emeritus, Faculty of Health Sciences, Universidade de Brasilia, 70919-970 Brasilia, DF, Brazil.
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Teles NMM, Agostini MAP, Bigeli JG, Noleto RV, Oliveira JD, de Oliveira Junior WP. Molecular and parasitological detection of Leishmania spp. in dogs caught in Palmas, TO, Brazil. ACTA ACUST UNITED AC 2013; 21:278-82. [PMID: 23070439 DOI: 10.1590/s1984-29612012000300017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 04/04/2012] [Indexed: 11/21/2022]
Abstract
This study evaluated occurrences of Leishmania infantum in dogs in the municipality of Palmas, Tocantins, comparing diagnostic data obtained using the polymerase chain reaction (PCR) and parasitological diagnosis. Blood samples and lymph node aspirates were collected from 63 dogs of males and females and various ages and races, with or without owners, between August 2009 and June 2010. Slides containing smears of lymph node aspirates were stained with Giemsa stained. In PCR, the 145 bp target sequence of the LT1 fragment, located in the Leishmania donovani kDNA minicircle was detected using the RV1 and RV2 oligonucleotide primers. The chi-square test revealed that there was a significant relationship between the symptoms and dogs that were positive for visceral leishmaniasis (VL). The parasitological investigation showed concordance of 66.7% with PCR on blood and 84.1% with PCR on lymph node aspirate. In addition to these tests, evaluations of the diagnoses in parallel and in series were conducted, which showed concordances with the parasitological test of 76.2% and 74.6%, respectively. The results make it possible to suggest that PCR on lymph nodes should be used in evaluating large populations (surveys) and that the parasitological test should be used for initial clinical evaluations in veterinary consultation offices.
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Fraga DBM, Solcà MS, Silva VMG, Borja LS, Nascimento EG, Oliveira GGS, Pontes-de-Carvalho LC, Veras PST, dos-Santos WLC. Temporal distribution of positive results of tests for detecting Leishmania infection in stray dogs of an endemic area of visceral leishmaniasis in the Brazilian tropics: a 13 years survey and association with human disease. Vet Parasitol 2012; 190:591-4. [PMID: 22795669 DOI: 10.1016/j.vetpar.2012.06.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
Human visceral leishmaniasis occurs in periodic waves in endemic areas of Brazil. In this study we followed the prevalence of human visceral leishmaniasis and of Leishmania infantum infection in stray dogs of an endemic area of visceral leishmaniasis at periods of time between 1997 and 2010. Prevalence of human visceral leishmaniasis had two peaks (40 cases) in 1997 and 2006 with sharp declines to 2 cases in 2001 and to 5 cases in 2008. Similar fluctuations were also observed in the occurrence of positive spleen culture and anti-Leishmania serology in dogs, although the proportion of dogs with active spleen parasitism remained relatively high even in the periods of low prevalence of human disease. These observations support the notion that stray dogs may constitute a renewable source of parasites, capable of sustaining the persistence of the infection in urban areas, even in periods of low transmission by phlebotomines.
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Affiliation(s)
- Deborah B M Fraga
- Fundação Oswaldo Cruz (Fiocruz), Centro de Pesquisas Gonçalo Moniz, Rua Waldemar Falcão 121, Candeal, Salvador 40-296-710, BA, Brazil
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Bigeli JG, Oliveira Júnior WPD, Teles NMM. Diagnosis of Leishmania (Leishmania) chagasi infection in dogs and the relationship with environmental and sanitary aspects in the municipality of Palmas, state of Tocantins, Brazil. Rev Soc Bras Med Trop 2012; 45:18-23. [DOI: 10.1590/s0037-86822012000100005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 08/08/2011] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: The aim of the present study was to identify the presence of Leishmania (Leishmania) chagasi infection in dogs in the City of Palmas, Tocantins, Brazil, using the PCR technique to list the hot spots of infected dogs in the city and associate their occurrence to significant environmental changes at capture sites. METHODS: DNA was extracted from blood of dogs, and the PCR were performed with primers RV1/RV2. After screening the population studied, the regions of the city that had the highest occurrence of canine infection were detected. These sites were visited, and ecological parameters denoting anthropogenic disturbance were evaluated. RESULTS: Some important features were listed in the regions visited, such as low urbanization, lack of public collection of sewage, limited garbage collection, vacant lots with tall vegetation, decaying organic matter, and, most importantly, the occurrence of stray dogs and poultry in homes. CONCLUSIONS: The methodology for screening the population was very efficient, especially in evaluating a large number of individuals in a short time, with a high degree of automation. The results indicate an association between the observed parameters and the occurrence of infection in dogs. The model presented in the city is ideal for studies of disease progression and expansion and for the evaluation of control measures adopted for canine VL.
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Teixeira MCA, Oliveira GGDS, Santos POM, Bahiense TC, Silva VMGD, Rodrigues MS, Larangeira DF, dos-Santos WLC, Pontes-de-Carvalho LC. An experimental protocol for the establishment of dogs with long-term cellular immune reactions to Leishmania antigens. Mem Inst Oswaldo Cruz 2011; 106:182-9. [DOI: 10.1590/s0074-02762011000200011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Accepted: 12/01/2010] [Indexed: 12/31/2022] Open
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Santana CC, Vassallo J, de Freitas LAR, Oliveira GGS, Pontes-de-Carvalho LC, dos-Santos WLC. Inflammation and structural changes of splenic lymphoid tissue in visceral leishmaniasis: a study on naturally infected dogs. Parasite Immunol 2008; 30:515-24. [PMID: 18665902 PMCID: PMC2592477 DOI: 10.1111/j.1365-3024.2008.01051.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 05/28/2008] [Indexed: 11/30/2022]
Abstract
The aim of this study was to identify splenic immuno-inflammatory patterns associated with natural infection by Leishmania chagasi. Spleen samples were obtained from 72 stray dogs from an endemic area of visceral leishmaniasis. The animals were grouped into four categories as follows: (i) potentially resistant to visceral leishmaniasis, with a positive leishmanin skin test result, and negative splenic culture for Leishmania parasites (ii) potentially susceptible to visceral leishmaniasis, with a negative leishmanin skin test and positive splenic culture for Leishmania (iii) infected with undefined susceptibility status, with a positive leishmanin skin test and positive splenic culture for Leishmania, and (iv) noninfected, with a negative leishmanin skin test, negative splenic culture for Leishmania, and negative serology for anti-Leishmania antibodies. Histopathological analyses showed that there was a higher frequency of perisplenitis (18/25, P < 0.0001), granuloma (7/25, P = 0.0102), structural disorganization (14/25, P < 0.0001), and atrophy of the lymphoid follicles (20/25, P = 0.0036) and of the marginal zone (15/25, P = 0.0025) in the potentially susceptible group than in the other groups. The data presented here show changes in the white pulp of the spleen that are associated with naturally acquired visceral leishmaniasis.
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Affiliation(s)
- C C Santana
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Fundação Oswaldo Cruz, Candeal, Salvador, Bahia, Brazil
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Dos-Santos WLC, Jesus EE, Paranhos-Silva M, Pereira AM, Santos JC, Baleeiro CO, Nascimento EG, Moreira ED, Oliveira GGS, Pontes-de-Carvalho LC. Associations among immunological, parasitological and clinical parameters in canine visceral leishmaniasis: Emaciation, spleen parasitism, specific antibodies and leishmanin skin test reaction. Vet Immunol Immunopathol 2008; 123:251-9. [PMID: 18359091 DOI: 10.1016/j.vetimm.2008.02.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 12/27/2007] [Accepted: 02/08/2008] [Indexed: 10/22/2022]
Abstract
Associations among parameters commonly used as markers of infection by Leishmania sp., or of susceptibility to visceral leishmaniasis, were investigated in 325 stray dogs from an area where this disease is endemic. Evidence of infection (presence of Leishmania in splenic cultures, positive leishmanin skin test (LST) or detection of anti-Leishmania antibody activity in the serum) was found in 57% of the animals. Both evidence of weight loss (chi(2)-test, P=0.0005) and presence of specific antibody activity in the serum (chi(2)-test, P<0.0001) were directly associated with positive splenic culture. The frequencies of animals with positive splenic culture were directly correlated with the intensities of antibody activity in the serum as measured by ELISA (relative risk of 3.4 for animals with moderate antibody levels and relative risk of 8.43 for animals with high-antibody levels). A negative association was observed between positive leishmanin skin test results and emaciation (chi(2), P=0.0089). Furthermore, animals with positive splenic cultures and negative leishmanin skin test results had higher levels of total serum IgG (Kruskal-Wallis test, P=0.001) and IgG2 (Kruskal-Wallis test, P=0.05) than animals with negative splenic cultures, and were more emaciated than animals with negative LST results and positive splenic cultures. The data presented herein suggest that associating these common parameters may improve their performance in predicting susceptibility to canine visceral leishmaniasis.
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Affiliation(s)
- W L C Dos-Santos
- Centro de Pesquisas Gonçalo Moniz-FIOCRUZ, Fundação Oswaldo Cruz, Rua Waldemar Falcão 121, Candeal, 40.296-710 Salvador, BA, Brazil
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Baleeiro CO, Paranhos-Silva M, dos Santos JC, Oliveira GGS, Nascimento EG, de Carvalho LP, dos-Santos WLC. Montenegro's skin reactions and antibodies against different Leishmania species in dogs from a visceral leishmaniosis endemic area. Vet Parasitol 2006; 139:21-8. [PMID: 16567046 DOI: 10.1016/j.vetpar.2006.02.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 02/21/2006] [Accepted: 02/24/2006] [Indexed: 11/24/2022]
Abstract
In this study, humoral (circulating anti-Leishmania antibodies) and cellular (Montenegro's skin test) immune responses of dogs from an endemic area of visceral leishmaniosis were tested using Leishmania chagasi, Leishmania amazonensis and Leishmania braziliensis antigens. The antibody response was tested in three animal groups, selected according to their anti-L. chagasi antibody activity, as measured by ELISA in the serum: 19 negative (O.D. below 0.30), seven with undefined (O.D. between 0.40 and 0.70) and 12 positive (O.D. above 1.0) ELISA result. In the group of animals with positive ELISA, the antibody activity against L. chagasi antigens (mean O.D.=1.31) was significantly higher (ANOVA, P<0.01) than against L. amazonensis (mean O.D.=0.88) or L. braziliensis (mean O.D.=0.87) antigens. The Montenegro's skin test results obtained with L. chagasi and L. braziliensis antigens showed a fair agreement (kappa=0.309). The same was observed when antigens from L. braziliensis and L. amazonensis were compared (kappa=0.374), whereas a moderate agreement between the results from tests performed with L. chagasi and L. amazonensis antigens was observed (kappa=0.530). The induration areas obtained with L. braziliensis antigen were smaller than those obtained with the other antigens. The data presented herein indicate that the use of antigens from different Leishmania species may interfere with the results of the immunological tests performed in dogs in an endemic area of visceral leishmaniosis.
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Affiliation(s)
- Carolina O Baleeiro
- Centro de Pesquisas Gonçalo Moniz-Fiocruz, Fundação Oswaldo Cruz, Rua Waldemar Falcão 121, 40295-001 Salvador (BA), Brazil
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Mayrink W, Coelho GLLM, Guimarães TMPD, de Andrade HM, de Castro Peres E, da Costa CA, de Toledo VDPCP. Immuno-biochemical evaluations of phenol and thimerosal as antigen preservatives in Montenegro skin test. Acta Trop 2006; 98:87-93. [PMID: 16527224 DOI: 10.1016/j.actatropica.2006.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 01/27/2006] [Accepted: 02/10/2006] [Indexed: 11/20/2022]
Abstract
Montenegro skin test (MST) represents the main complementary diagnostic test for tegumentary leishmaniases (TL) in endemic regions. Most antigen formulations used for the MST contain thimerosal as preservative. The Food and Drug Administration (FDA), however, recommended reducing or eliminating thimerosal from vaccines and other biological reagents and the Agência Nacional de Vigilância Sanitária (ANVISA) in Brazil, prohibited the use of mercurial compounds in immunobiologicals. In the search for an alternative stabilizer, phenol and thimerosal were tested as antigen preservatives in MST. Formulations were tested when fresh and after a 12-month storage at 4 degrees C in TL confirmed mice and human patients, and were evaluated for protein constitution by SDS-PAGE, Western blot and anti-gp63 ELISA. In mice, a decrease in the diagnostic effectiveness in merthiolate formulation was observed after a 12-month storage. SDS-PAGE, Western blot and anti-gp63 ELISA analyses showed a degradation of antigen proteins in both formulations after 12-month storage and that phenol-preserved antigen was quantitatively and qualitatively better than the merthiolate-preserved one. In patients, the average of induration diameter was larger in fresh antigens (p<0.05). However, storage time did not jeopardize their diagnostic capacity. No non-specific reactions produced by phenol or merthiolate were observed neither in humans nor in mice. Phenol could be a good alternative to replace the merthiolate in MST, and despite the proteolytic activity, antigens remain viable for at least 12 months.
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Affiliation(s)
- Wilson Mayrink
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Depto de Parasitologia, Brazil
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de Lima Barros MB, Schubach A, Francesconi-do-Valle AC, Gutierrez-Galhardo MC, Schubach TMP, Conceição-Silva F, de Matos Salgueiro M, Mouta-Confort E, Reis RS, de Fátima Madeira M, Cuzzi T, Quintella LP, da Silva Passos JP, Conceição MJ, de Almeida Marzochi MC. Positive Montenegro skin test among patients with sporotrichosis in Rio De Janeiro. Acta Trop 2005; 93:41-7. [PMID: 15589796 DOI: 10.1016/j.actatropica.2004.09.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2004] [Revised: 09/05/2004] [Accepted: 09/13/2004] [Indexed: 11/24/2022]
Abstract
We studied 52 patients with sporotrichosis confirmed by isolation of Sporothrix schenckii and reactivity to the Montenegro skin test (MST) during an ongoing outbreak of this mycosis in Rio de Janeiro. The objective was to emphasize the importance of parasitological confirmation and the possibility of incorrect diagnosis based on the lesion's appearance, epidemiological information, and immunological tests. The antigen used for the MST was conserved in either thimerosal 1:10,000 (group 1) or 0.4% phenol (group 2). Nineteen patients (39%) in group 1 and seven (12%) in group 2 presented an induration>or=10 mm (p<0.001). Sera from three patients (6.7%) reacted to indirect immunofluorescence (IIF) for leishmaniasis, while sera from 10 patients (22.2%) reacted to enzyme-linked immunosorbent assay (ELISA). Fifteen patients (28.8%) presented up to two lesions, with a predominance of ulcers. Forty-four patients (84.6%) were treated with itraconazole. In the differential diagnosis between sporotrichosis and cutaneous leishmaniasis, the possibility of co-infection, allergy to the reagent diluent, and cross-reactions should be further investigated, especially in regions with limited laboratory facilities.
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Affiliation(s)
- Mônica Bastos de Lima Barros
- Instituto de Pesquisa Clínica Evandro Chagas (IPEC), Fundação Oswaldo Cruz (Fiocruz), Av. Brasil 4365, Manguinhos, Rio de Janeiro CEP 21045-900, Brazil.
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