Agriculture Reference
In-Depth Information
Another method developed to amplify DNA is the loop-mediated isothermal amplification
(LAMP) assay. Based on a previous review, Parida et al. (2008) stated that LAMP is
characterized by the use of six different primers. Amplification and detection of a gene can be
completed in a single step, by incubating the mixture of samples, primers, DNA polymerase
with strand displacement activity and substrates, at a constant temperature. The result is based
on naked eye observations of a white precipitate (magnesium pyrophosphate). Thus, the
method does not require expensive equipments, such as thermal cyclers or reagents.
5. Global prevalence of soil-transmitted zoonotic helminth infections in
humans and associated risk factors
Human
Toxocara
infection has a cosmopolitan distribution, but reliable prevalence estimates
are hard to derive from available serosurvey data, which comprises demographically
diverse population samples that may not be representative of the general population of their
respective countries, provinces or cities (Table 2).
Continent/
Country
No. of
samples
Positive
(%)
Site(s)
Reference
Africa
La Réunion
90 districts
387
C
92.8
Magnaval et al. (1994)
Americas
U.S.A.
Various areas
20,395
AC
13.9
Won et al. (2008)
Argentina
La Plata
156
AC
46.9
Radman et al. (2000)
Resistencia
206
C
37.9
Alonso et al. (2000)
Assis Brasil and
Acrelândia
Brazil
606
C
21.5
Ferreira et al. (2007)
São Paulo city
399
C
38.8
Alderete et al. (2003)
Campinas
138
AC
27.7
Anaruma et al. (2002)
Rubinsky-Elefant et al.
(2008)
Granada
403
AC
26.8
Pres. Prudente
252
C
11.1
Santarém et al. (2011)
Teodoro Sampaio
(settlement)
Prestes-Carneiro
et al. (2008)
79
AC
21.5
São Paulo city
338
C
26.9
Muradian et al. (2005)
Sorocaba
180
C
38.3
Coelho et al. (2004)
Peru
Lima
303
AC
20.5
Espinoza et al. (2010)
Asia
Iran
Sari City
1,210
C
25.0
Sharif et al. (2010)
Taiwan
Districts in East
329
C
76.6
Fan et al. (2004a)
463
A
28.6
Gonzalez-Quintela et al.
(2006)
Table 3. Seroprevalences for human toxocariasis on different continents. Adapted from
Rubinsky-Elefant et al. (2010). (Population studied: adult
A
; children
C
).
Europe
Spain
Santiago de
Compostela
Toxocariasis tends to be more prevalent in tropical settings, compared to temperate regions,
while rural populations are usually more exposed than urban populations in the same
region (Rubinsky-Elefant et al., 2010). Reported seroprevalence rates in apparently healthy
