Spelling suggestions: "subject:"trichuriasis"" "subject:"trichiasis""
1 |
Treatment and prevention of trichuriasis : efficacy of albendazole in disadvantaged children at Rawsonville Primary School, Western Cape Province, South AfricaArendse, Vera Jane 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Children in socioeconomically disadvantaged communities in the Western Cape and elsewhere in South
Africa are frequently infected by Trichuris trichiura. Although albendazole and mebendazole are listed
as essential drugs for treatment of humans, it is well known that trichuriasis is relatively refractory to
anthelmintic treatment. There are some reports that mebendazole is more effective against Trichuris and
it is available as generics that are relatively cheap. On the other hand, albendazole is better for
hookworm and may have some effect against Giardia duodenalis, which is common in the same
communities. Moreover, albendazole is used in a deworming programme in KwaZulu-Natal, at a dose
o f400 mg stat, given once or twice a year depending on the health region in that province.
In terms of diagnosis, infection by intestinal helminthiasis can be determined and monitored by simple,
non-invasive, sustainable and cost effective methods. The epidemiological significance of high
prevalence extends far beyond the worms per se because they are an index of environmental conditions
that pose a risk of several other diseases. These include infection by organisms that can cause epidemics
of enteric disease. These facts pertain within a deteriorating milieu in terms of human ecology, because
the informal sector of the population is burgeoning under dynamic forces that include urbanisation,
migration, poverty and disease.
The study reported in this thesis had three main objectives within the context and concepts of the
realities described in the previous two paragraphs. The first was to review and consider all information
on trichuriasis that could be detected in the literature, and to relate the result to South African needs.
The second was to test efficacy of albendazole against trichuriasis in children from a community where
it is the predominant worm infection, by means of a well designed and controlled study. Finally, it was necessary to consider other results associated with treatment. These included possible drug resistance
and effects on growth, eosinophilia, iron status and toxicity.
The literature survey established that South Africa lags behind many other developing countries in
defining and addressing the problem of helminthiasis as a whole. The conventional epidemiology of
trichuriasis as described in the literature is based mainly on studies in the West Indies. Surveys
completed recently in the Western Cape Province of South Africa confirm some of the epidemiological
concepts, with two notable exceptions. First, the age-related prevalence peaked in children who were
14 years old in a suburb of Cape Town. This is older that in West Indian children. The second
difference is probably more important and was detected in children at schools serving the informal sector
o f Khayelitsha. This is densely populated and the sanitation is often not effective and is sometimes
totally lacking. The distribution of egg counts in 316 Khayelitsha children was not overdispersed to low
counts, which is perceived as invariably the situation in the West Indies. In the Khayelitsha survey,
approximately 25% of children had more than 10 000 eggs per g of faeces.
The randomised controlled treatment trial tested a series of four albendazole treatments, at doses of400,
800 and 1200 mg (given as 400 mg/day), repeated at intervals of approximately four months in matched
groups of children. Results indicate that mass deworming programmes in South Africa should not use
albendazole at a dose o f400 mg stat for control of infection by Trichuris trichiura. The package insert
of the product tested (Zentel®, SmithKline Beecham) recommends that "in heavy mixed infestation
involving Trichuris, a single daily dose may be inadequate and the dose may be given for three
consecutive days". This statement is not accurate because even when infection by Trichuris was not
intense, as defined internationally in terms of egg counts per g of faeces, and it was the only helminth
present, the cure rate achieved by repeated doses of 400 mg of albendazole was not satisfactory.
Moreover, 48% (15/31) of treated children remained continuously infected, although egg counts were clearly reduced. This result demonstrates that continuous use of a dose of 400 mg which is the
maximum stat dose permitted in South Africa, is likely to facilitate development of true genetic
resistance to albendazole by T. trichiura. Doses of 800 and 1200 mg were more efficacious and
continuous infection reduced to 21% (9/43) and 2.5% (1/39), respectively. A dose of 800 mg for
routine use in mass deworming programmes, as 400 mg/day, can be recommended on the basis of
sufficiently efficacious treatment, simplification of compliance, and reduction of cost. The frequency
of treatment within such programmes should probably be three times per year when prevalence of severe
infection exceeds 10% ("severe infection" is defined internationally as an egg count of more that 10 000
per g of faeces). When severe infection is less frequent, treatment could be less often, but more
definitive research of this aspect is necessary under local conditions. There was some evidence that
incidence increased seasonally during summer and autumn in the community concerned.
A range of other results was recorded. The possibility of genetic resistance to albendazole by Trichuris
trichiura was not excluded. There was significant reduction of eosinophiha during treatment with
albendazole. This may have immunological implications for incidence, prevention and progression of
other diseases. Treatment appeared to be beneficial in terms of growth and iron status, but there was
not sufficient statistical power to confirm this. No evidence of toxicity at the highest dose (1200 mg
given as 400 mg/day for three days) was detected. / AFRIKAANSE OPSOMMING: Kinders in sosio-ekonomiese agterblewe gemeenskappe in die Wes-Kaap en ook elders in Suid-Afrika
toon gereelde infeksies met Trichuris trichiura. Albendazool en mebendazool word gelys as
noodsaaklike medikasie vir menslike behandeling, maar dit is wel bekend dat Trichuris relatief moeilik
is omte behandel. Daar word gerapporteer dat mebendazool meer effektief is teen Trichuris en maklik
beskikbaar is as goedkoper generiese medikasie. Albendazool, aan die ander kant, is effektief teen
haakwurm en kan ook ‘n effek het teen Giardia duodenalis, wat voorkom in dieselfde gemeenskappe.
‘n Dosis van 400 mg albendazool, een of twee keer per jaar, word huidelik gebruik in ‘n
onwurmingsprogram in KwaZulu-Natal. Die frekwensie van behandeling word bepaal deur die
gesondheids streek binne die provinsie.
In terme van diagnose, kan infeksie deur intestinale helminte bepaal en gemonitor word deur eenvoudige,
nie-invallende, koste effektiewe maniere. Die epidemiologiese betekenis van ‘n hoe voorkoms strek
verder as net die wurms omdat hulle ‘n indeks is van omgewings besoedeling wat kan dui op die risiko
van verskeie ander siektes. Dit sluit in infeksies deur organismes wat epidemies van enteriese siektes
veroorsaak. Hierdie feite pas binne die agteruitgang in terme van menslike ekologie, want die informele
sektor van die bevolking is onder dinamiese druk wat verstedeliking, migrasie armoede en siektes insluit.
Die studie, waarvan verslag gegee word in hierdie tesis, het drie vemame objektiewe binne die konteks
en konsepte van die realiteite soos beskryf in die vorige twee paragrawe. Die eerste objektief was om
alle informasie aangaande trichuriase in die literatuur in oorsig te neem en dit in verband te bring met
Suid-Afrikaanse behoeftes. Die tweede was om die werksaamheid van albendazool teen trichuriase te
toets in kinders van ‘n gemeenskap waar wurm infeksies oorheers, deur middel van ‘n goed beplande
en gekontroleerde studie. Laastens was dit nodig om ander resultate, geassosieer met behandeling, in ag te neem. Dit sluit in moontlike weerstand teen die medikasie en die effek op groei, ysterstatus en
toksisiteit.
Die literatuur oorsig toon dat Suid-Afrika ‘n agterstand het met baie ander ontwikkelende lande om die
omslag van die probleem van helminte te bepaal en ook om dit aan te pak. Die konvensionele
epidemiologie van trichuriase, soos beskryf in die literatuur, is gegrond op studies in die Wes-Indies.
Opnames wat onlangs in die Wes-Kaap gedoen is, bevestig sekere epidemiologiese konsepte met twee
vemame uitsonderings. Die eerste is die ouderdoms verwante voorkoms wat ‘n hoogtepunt bereik in
14 jarige kinders in ‘n voorstad van Kaapstad. Dit is ouer as in die Wes-Indiese kinders. Die tweede
verskil is miskien meer belangrik en was vasgestel in skool kinders in ‘n informele sektor van
Khayelitsha. Dit is ‘n dig bewoonde area met oneffektiewe of ‘n totale gebrek aan sanitasie. Die
verspreiding van eier tellings in 316 Khayelitsha kinders was nie oor-versprei tot lae tellings nie, wat
andersins die geval in die Wes-Indies was. In die Khayelitsha studie het ongeveer 25% van kinders meer
as 10 000 epg stoelgang.
Die gekontrolleerde ewekansigheidstoets soos bespreek in hierdie tesis het ‘n reeks van vier albendazool
behandelings, by dosisse van 400, 800 en 1200 mg (gegee as 400 mg/dag), herhaal by pouses van
ongeveer vier maande in gelyke groepe van kinders, ge-evalueer. Die resultate toon dat massa
ontwurmings programme in Suid-Afrika nie die 400 mg dosis vir kontrole van Trichuris trichiura moet
gebruik nie. Die pakkie insetsel van die produk wat getoets was (Zentel®, SmithKline Beecham) dui
aan dat in swaar gemengde infeksies waar Trichuris betrokke is, ‘n enkele dosis onvoldoende is en dat
die dosis vir drie agtereenvolgende dae gegee mag word. Hierdie stelling is onakkuraat want al is die
infeksie deur Trichuris nie swaar nie, soos intemasionaal gedefinieer in terme van eier telling per gram
stoelgang, en al is dit die enigste intestinale wurm teenwoordig, is die genesingsyfer wat behaal is met
herhaalde dossise van 400 mg albendazool nie bevredigend nie. Inteendeel, 48% (15/31) van behandelde kinders was aanhoudend besmet, al was eier tellings duidelik verminder.
Hierdie resultaat wys dat herhaaldelike gebruik van ‘n 400 mg dosis, wat die maksimim dosis toelaatbaar
in Suid-Afrika is, genetiese weerstand van albendazool deur Trichuris trichiura kan fasiliteer. Die 800
mg en 1200 mg dosis was meer doeltreffend en het herhaalde infeksie verminder tot 21 % (9/43) en 2.5%
(1/39) onderskeidelik. Die 800 mg dosis as 400 mg/dag word aanbeveel vir roetine gebruik in massa
ontwurmings programme. Dit is meer doeltreffend, behandeling word vereenvoudig en koste word
verminder. Die frekwensie van behandeling binne sulke programme moet waarskynlik drie keer per jaar
wees wanneer die prevalensie van swaar infeksies meer as 10% is (“swaar infeksie” word intemasionaal
gedefinieer, wanneer eier tellings meer as 10 000 eiers per g stoelgang is). As swaar infeksies minder
voorkom, kan behandeling minder gereeld wees, maar meer bepaalde navorsing onder plaaslike kondisies
is nodig. Daar is sekere bewysse dat insidensie seisoenaal verminder, tydens somer en herfs, in hierdie
gemeenskap.
‘n Reeks van ander resultate was ook aangeteken. Die moontlikheid van genetiese weerstand van
Trichuris trichiura teen albendazool word nie uitgesluit nie. Daar was ‘n aanmerklike vermindering van
eosinophillia tydens behandeling met albendazool. Dit mag immunologiese implikasies vir insidensie,
voorkoming en voortgang van ander siektes voorspel. Dit blyk of behandeling groei en yster status
bevoordeel het, maar daar was nie genoegsame statistiese mag om dit te bevestig nie. Geen bewys van
vergiftiging by die hoogste dosis (1200 mg gegee as 400 mg/dag vir drie dae) is waargeneem nie.
|
2 |
Paleogenética e paleoepidemiologia de Ascaris sp. (Linnaeus, 1758) e Trichuris sp. (Roederer, 1761) / Paleogenetics paleoepidemiology and Ascaris sp. (Linnaeus, 1758) and Trichuris sp. (Roederer, 1761)Souza, Daniela Leles de January 2010 (has links)
Made available in DSpace on 2011-05-04T12:42:02Z (GMT). No. of bitstreams: 0
Previous issue date: 2010 / Ascaris lumbricoides e Trichuris trichiura são os helmintos intestinais de maior prevalência na população mundial e também no material arqueológico. Porém, na América do Sul pré-colombiana, o encontro de ovos de A. lumbricoides é raro. Recentemente um estudo de diagnóstico paleoparasitológico molecular apontou para um sub-diagnóstico de Ascaris sp. na América do Sul. No registro arqueológico de parasitos intestinais predominam achados de ovos de Trichuris sp. ao invés de Ascaris sp. Isto parece
contraditório, em virtude do número de ovos eliminados por cada parasito. Os objetivos desta pesquisa foram: avaliar marcadores moleculares para o diagnóstico de Ascaris sp. e Trichuris sp. em material moderno pela caracterização molecular destes parasitos; caracterizar geneticamente isolados de sítios arqueológicos sul americanos para verificar a real paleodistribuição destes parasitos em uma perspectiva paleoepidemiológica e
compará-la com a epidemiologia moderna destas infecções; avaliar os fatores envolvidos na paleodistribuição encontrada. As amostras foram submetidas ao diagnóstico por microscopia óptica, seguida da extração do DNA, PCR e sequenciamento nucleotídico. Na avaliação dos marcadores moleculares, a região ITS1 de Ascaris sp. apresentou variação intra-indivíduo, o que descartou seu uso com fins taxonômicos e diagnósticos. A caracterização molecular dos genes mitocondriais cox1 e nad1 de Ascaris sp. mostrou infecção cruzada de genótipos entre as espécies humana e suína, o que denota a necessidade de monitoramento das populações avaliadas assim como de outras regiões brasileiras para que a infecção não venha a se tornar uma zoonose em potencial no Brasil.
Foi possível o diagnóstico molecular de Trichuris sp. pelo gene ribossomal 18S DNA. A análise paleogenética mostrou que há subdiagnóstico para ambas as infecções na América do Sul pré-colombiana. Este é o primeiro diagnóstico paleoparasitológico molecular de T. trichiura em material sul americano. Estes são também os primeiros registros de recuperação de DNA de parasitos intestinais em material de sítio arqueológico do tipo “sambaqui” e também do período colonial brasileiro. Comparando-se a paleoepidemiologia molecular de Ascaris sp. com a epidemiologia molecular moderna foi possível notar que há haplótipos antigos que ainda estão presentes hoje, no entanto a maioria dos haplótipos é característica ao material arqueológico. Observou-se que há haplótipos comuns ao Velho e Novo Mundo, contudo, há também especificidades regionais. Os resultados da análise genética claramente apontam para uma pobre preservação dos ovos no material arqueológico, principalmente de Ascaris sp. Os fatores principais envolvidos nessa paleodistribuição, seriam fatores tafonômicos que proporcionaram a quebra maior de ovos de Ascaris sp. do que de Trichuris sp., e evidências de consumo de plantas vermífugas pelos povos pré-históricos, as quais teriam maior ação sobre Ascaris sp. do que Trichuris sp. / Ascaris lumbricoides and Trichuris trichiura are the intestinal helminths with higher prevalence in the world today as it was in the past. However, in pre-Columbian South America the findings of A. lumbricoides eggs are rare. Recently a study of paleoparasitological molecular diagnosis showed a sub-diagnosis of Ascaris sp. in South America. In the archeological material, eggs of Trichuris sp. are more common compared with Ascaris sp. eggs. This is contradictory taking into account the number of eggs eliminated by each parasite. The aims of this research was: to evaluate molecular markers
for Ascaris sp. and Trichuris sp. diagnosis in modern material; genetic characterization of the samples South American archeological sites aiming the paleodistribution of these parasites in a paleoepidemiological perspective; compare results with the modern epidemiology of these infections; evaluate the factors involved in paleodistribution. Extraction of DNA, PCR and nucleotide sequencing were performed after microscopy. In the evaluation of the molecular markers Ascaris sp. ITS1 region showed intra-individual variation. Therefore, this region to taxonomical and diagnoses studies was discarded. With the molecular characterization of Ascaris sp. cox1 and nad1 mitochondrial genes it was
possible to identify cross infection of genotypes between human and pig hosts. Results showed that surveillance field works in modern populations are necessary to verify the zoonotic potential of this infection in Brazil. The molecular diagnosis of Trichuris sp. by ribossomal 18S DNA gene was possible. The paleogenetic analysis showed that there is subdiagnosis for both infections in pre-Columbian South America. This is the first
paleoparasitological molecular record of T. trichiura in South American samples. These
are also the first recovery of DNA of intestinal parasites in "sambaqui" archeological site, and also of the Brazilian colonial period. Molecular paleoepidemiology of Ascaris sp. infection compared with modern molecular epidemiology showed that there are ancient haplotypes still present today. However, most of the haplotypes are characteristic of the archaeological material. It was observed that there are common haplotypes both to the Old World and to the New World, but showing regional specificities. The results of the genetic analysis clearly pointed to a poor preservation of eggs in archeological material, mainly of Ascaris sp. Taphonomy may be the main factor involved in paleodistribution, breaking more eggs of Ascaris sp. than Trichuris sp. Evidences of consumption of vermifuge plants by prehistoric groups should also have influence, as some plants should have more efficacy eliminating Ascaris sp. than Trichuris sp.
|
Page generated in 0.0487 seconds