Zaida Herrador

Dr. Zaida Herrador

orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 September 2018 in Malaria Journal
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PBPedro J. Berzosa
Pedro J. Berzosa
ALAida de Lucio
Aida de Lucio
MRMaría Romay-Barja
María Romay-Barja
ZHZaida Herrador
Zaida Herrador
VGVicenta González
Vicenta González
ABAgustín Benito
Agustín Benito
Malaria in Equatorial Guinea remains a major public health problem. The country is a holo-endemic area with a year-round transmission pattern. In 2016, the prevalence of malaria was 12.09% and malaria caused 15% of deaths among children under 5 years. In the Continental Region, 95.2% of malaria infections were Plasmodium falciparum, 9.5% Plasmodium vivax, and eight cases mixed infection in 2011. The main strategy for malaria control is quick and accurate diagnosis followed by effective treatment. Early and accurate diagnosis of malaria is essential for both effective disease management and malaria surveillance. The quality of malaria diagnosis is important in all settings, as misdiagnosis can result in significant morbidity and mortality. Microscopy and RDTs are the primary choices for diagnosing malaria in the field. However, false-negative results may delay treatment and increase the number of persons capable of infecting mosquitoes in the community. The present study analysed the performance of microscopy and RDTs, the two main techniques used in Equatorial Guinea for the diagnosis of malaria, compared to semi-nested multiplex PCR (SnM-PCR). A total of 1724 samples tested by microscopy, RDT, and SnM-PCR were analysed. Among the negative samples detected by microscopy, 335 (19.4%) were false negatives. On the other hand, the negative samples detected by RDT, 128 (13.3%) were false negatives based on PCR. This finding is important, especially since it is a group of patients who did not receive antimalarial treatment. Owing to the high number of false negatives in microscopy, it is necessary to reinforce training in microscopy, the “Gold Standard” in endemic areas. A network of reference centres could potentially support ongoing diagnostic and control efforts made by malaria control programmes in the long term, as the National Centre of Tropical Medicine currently supports the National Programme against Malaria of Equatorial Guinea to perform all of the molecular studies necessary for disease control. Taking into account the results obtained with the RDTs, an exhaustive study of the deletion of the hrp2 gene must be done in EG to help choose the correct RDT for this area.

29 September 2014 in PLOS ONE
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ZHZaida Herrador
Zaida Herrador
LSLuis Sordo
Luis Sordo
EGEndalamaw Gadisa
Endalamaw Gadisa
JMJavier Moreno
Javier Moreno
JNJavier Nieto
Javier Nieto
ECEstefania Custodio
Estefania Custodio
Little information is available on malnutrition-related factors among school-aged children ≥5 years in Ethiopia. This study describes the prevalence of stunting and thinness and their related factors in Libo Kemkem and Fogera, Amhara Regional State and assesses differences between urban and rural areas. In this cross-sectional study, anthropometrics and individual and household characteristics data were collected from 886 children. Height-for-age z-score for stunting and body-mass-index-for-age z-score for thinness were computed. Dietary data were collected through a 24-hour recall. Bivariate and backward stepwise multivariable statistical methods were employed to assess malnutrition-associated factors in rural and urban communities. The prevalence of stunting among school-aged children was 42.7% in rural areas and 29.2% in urban areas, while the corresponding figures for thinness were 21.6% and 20.8%. Age differences were significant in both strata. In the rural setting, fever in the previous 2 weeks (OR: 1.62; 95% CI: 1.23–2.32), consumption of food from animal sources (OR: 0.51; 95% CI: 0.29–0.91) and consumption of the family's own cattle products (OR: 0.50; 95% CI: 0.27–0.93), among others factors were significantly associated with stunting, while in the urban setting, only age (OR: 4.62; 95% CI: 2.09–10.21) and years of schooling of the person in charge of food preparation were significant (OR: 0.88; 95% CI: 0.79–0.97). Thinness was statistically associated with number of children living in the house (OR: 1.28; 95% CI: 1.03–1.60) and family rice cultivation (OR: 0.64; 95% CI: 0.41–0.99) in the rural setting, and with consumption of food from animal sources (OR: 0.26; 95% CI: 0.10–0.67) and literacy of head of household (OR: 0.24; 95% CI: 0.09–0.65) in the urban setting. The prevalence of stunting was significantly higher in rural areas, whereas no significant differences were observed for thinness. Various factors were associated with one or both types of malnutrition, and varied by type of setting. To effectively tackle malnutrition, nutritional programs should be oriented to local needs.

14 March 2013 in The Journal of Infection in Developing Countries
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BABayeh Abera
Bayeh Abera
GAGenetu Alem
Genetu Alem
MYMulat Yimer
Mulat Yimer
ZHZaida Herrador
Zaida Herrador
Introduction: This study aimed to determine the prevalence of intestinal helminths, risk factors and haematocrit values among primary schoolchildren. Methodology: Across-sectional study was conducted in 12 primary schools in March 2011. Stool samples were randomly selected from 778 children and were microscopically examined using Kato-Katz and formal-ether concentration methods. Haematocrit values were measured using heparinized capillary tubes. Results: The overall prevalence of intestinal helminths was 51.5% (rural = 68.3%, urban = 36.2%). Hookworm spp., Schistosoma mansoni and Schistosoma stercoralis were more prevalent in rural schools, whereas Hymenolepis nana was higher in urban schools (p = 0.0001). With regard to haematocrit, 34% of rural and 21.7% of urban schoolchildren had haematocrit values below the median (40.5%) (p=0.001). Hookworm spp. and S. mansoni infected children had lower haematocrit values than non-infected children (p = 0.001). Lack of footwear was positively associated with intestinal helminths infection in rural schools [OR = 2.5 (95% CI: 1.5-4.1)], and having dirty fingernails and untrimmed fingernails were positively associated with the prevalence of intestinal helminths in urban samples [OR = 1.58 (95% CI: 1.03-2.5)]. Conclusion: The prevalence of soil-transmitted helminths and S. mansoni differs by geographical area of the schools and social determinants. Primary school de-worming and health education on proper hygiene are recommended.

25 June 2020 in Pathogens and Global Health
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CGChristine Giesen
Christine Giesen
JRJesús Roche
Jesús Roche
LRLidia Redondo-Bravo
Lidia Redondo-Bravo
CRClaudia Ruiz-Huerta Ruiz-Huerta
Claudia Ruiz-Huerta Ruiz-Huerta
DBDiana Gomez Barroso
Diana Gomez Barroso
ZHZaida Herrador
Zaida Herrador
Despite being one of the continents with the least greenhouse gas emissions, no continent is being struck as severely by climate change (CC) as Africa. Mosquito-borne diseases (MBD) cause major human diseases in this continent. Current knowledge suggests that MBD range could expand dramatically in response to CC. This study aimed at assessing the relationship between CC and MBD in Africa. Methods For this purpose, a systematic peer review was carried out, considering all articles indexed in PubMed, Scopus, Embase and CENTRAL. Search terms referring to MBD, CC and environmental factors were screened in title, abstract and keywords.Results A total of twenty-nine studies were included, most of them on malaria (61%), being Anopheles spp. (61%) the most commonly analyzed vector, mainly in Eastern Africa (48%). Seventy-nine percent of these studies were based on predictive models. Seventy-two percent of the reviewed studies considered that CC impacts on MBD epidemiology. MBD prevalence will increase according to 69% of the studies while 17% predicted a decrease. MBD expansion throughout the continent was also predicted. Most studies showed a positive relationship between observed or predicted results and CC. However, there was a great heterogeneity in methodologies and a tendency to reductionism, not integrating other variables that interact with both the environment and MBD. In addition, most results have not yet been tested. A global health approach is desirable in this kind of research. Nevertheless, we cannot wait for science to approve something that needs to be addressed now to avoid greater effects in the future.

28 July 2016 in PLOS ONE
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ALAida De Lucio
Aida De Lucio
AAAranzazu Amor-Aramendía
Aranzazu Amor-Aramendía
BBBegoña Bailo
Begoña Bailo
JSJose Maria Saugar
Jose Maria Saugar
MAMelaku Anegagrie
Melaku Anegagrie
David CarmenaDavid Carmena
David Carmena
Giardia duodenalis and Cryptosporidium spp. are enteric protozoan causing gastrointestinal illness in humans and animals. Giardiasis and cryptosporidiosis are not formally considered as neglected tropical diseases, but belong to the group of poverty-related infectious diseases that impair the development and socio-economic potential of infected individuals in developing countries. We report here the prevalence and genetic diversity of G. duodenalis and Cryptosporidium spp. in children attending rural primary schools in the Bahir Dar district of the Amhara Region, Ethiopia. Stool samples were collected from 393 children and analysed by molecular methods. G. duodenalis was detected by real-time PCR, and the assemblages and sub-assemblages were determined by multilocus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Detection and identification of Cryptosporidium species was carried out by sequencing of a partial fragment of the small-subunit ribosomal RNA gene. The PCR-based prevalences of G. duodenalis and Cryptosporidium spp. were 55.0% (216/393) and 4.6% (18/393), respectively. A total of 78 G. duodenalis isolates were successfully characterized, revealing the presence of sub-assemblages AII (10.3%), BIII (28.2%), and BIV (32.0%). Discordant typing results AII/AIII and BIII/BIV were identified in 7.7% and 15.4% of the isolates, respectively. An additional five (6.4%) isolates were assigned to assemblage B. No mixed infections of assemblages A+B were found. Extensive genetic variation at the nucleotide level was observed within assemblage B (but no within assemblage A), resulting in the identification of a large number of sub-types. Cryptosporidium diversity was demonstrated by the occurrence of C. hominis, C. parvum, and C. viatorum in the population under study. Our data suggest an epidemiological scenario with an elevated transmission intensity of a wide range of G. duodenalis genetic variants. Importantly, the elevated degree of genetic diversity observed within assemblage B is consistent with the occurrence of intra-assemblage recombination in G. duodenalis.

2 February 2012 in Eurosurveillance
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Open access
ALA Lenglet
A Lenglet
ZHZaida Herrador
Zaida Herrador
AMA P Magiorakos
A P Magiorakos
KLK Leitmeyer
K Leitmeyer
DCD Coulombier
D Coulombier
CSCollective European Working Group on Mycoplasma pneumoniae surveillance
Collective European Working Group on Mycoplasma pneumoniae surveillance
In January 2012, the European Centre for Disease Prevention and Control (ECDC) conducted an email-based survey of European Union and European Economic Area countries to describe the existing surveillance activities for Mycoplasma pneumoniae infections, recent findings and existence of clinical guidelines for the treatment of M. pneumoniae infection. Of the 20 countries that participated in the survey, seven reported increases in M. pneumoniae infections observed during the autumn and winter of 2011.