Abstract:
Cockroaches have adverse effects on human health and public health, especially as
they are a source of gastrointestinal tract diseases and perennial allergic reactions, which
results in considerable economic and medical losses. This study was to determine some
environmental factors and inhabitant behaviors which affect the prevalence and density of
cockroaches in various types of dwellings. The cross-sectional study of 250 household
samples was carried out in December 2002 to March 2003 in Nonthaburi Province. The
data on environmental dwelling factors and inhabitant behaviors were collected using
questionnaires and observation forms. Indoor cockroaches were collected with sticky traps
in 3 different places in each household for 3 consecutive nights, and they were then counted
and identified by species. Data were analyzed by using the Chi-Square Test of Association,
the Kruskal Wallis Test, the Mann-Whitney U Test and Spearman’s Correlation Coefficient
Analysis.
Results revealed that overall the prevalence of cockroaches was 55.2 %, while in
single houses, it was 60.0 %, in townhouses 48.3 %, in condominiums 32.0 %, in
apartments 62.2 % and in rented rooms 82.9 %. Average cockroach density was 2.4
cockroaches/trap, whereas in single houses, it was 1.94, in townhouses 1.88, in
condominiums 0.71, in apartments 2.23 and in rented rooms 6.71. Eight species were
found, namely Periplaneta americana, Supella longipalpa, P.brunnea, Blattella germanica,
P.australasiae, Neostylopyga rhombifolia, B.lituricallis and Pycnoscelus surinamensis.
Environmental dwelling and inhabitant behavior factors, such as type of dwelling, age of
dwelling, damaged and deteriorated conditions, material types of dwelling, rubbish and
waste, cooking behavior and cleaning behavior had statistically significant relationships
with the prevalence and density of cockroaches (p-value <0.05).
This study indicates that different species of cockroaches were spread all over and
captured in different types of households. These findings suggest that the results here
should be used as baseline data to lay out strategies in order to implement proper and better
control and prevention with regard to cockroaches. Cleanliness and food sanitation are
important factors in reducing the cockroach population, especially in damaged and
deteriorated dwellings, dwellings that share some parts with or are connected to other
dwellings. Dwellings should always be cleaned and kept neat and tidy; places for
cockroaches to hide should be removed; and cockroaches should be controlled by using a
combination of bait, sticky traps and, if necessary, chemical insecticides. Moreover, rubbish
and waste should properly be placed outside the building in a bin with a lid every night or
at least once daily. Washing dishes and utensils daily, sealing cracks and other portals of
entry as well as cooperation with neighbors are also suggested.