MEDICAL IMPORTANCE OF DOMICILIARY COCKROACHES

Lee Chow Yang, School o J ' B i o I o g i c a 1 S c i e n c e s , U n i v e r s i t i S a i n s : l fa lays ia . I l R O O P c n c l n ~ . . M a l a . ~ s i a

FLIX. 04-6565125, E m a i l : chowyang@,~l . rm.m,y

In/roduc/ion 7- 1 cake n h ~ c h 17 about to he s e n e d

C o c k r o a c h e s are a huccessful p r i n i ~ t i v c I i r rn o f insec t l i re . They are c la \ \ l r icd under t h e order o f I)ictyoptcr;~ u it11 t a ~ l ~ l l ~ e s ~ncluding Blattell~dac. L3la11idae. Polyphagidac . l3l;lheridae and o thers( ( 'on~uel l IC)hX). More than In00 bpcc~cs 111cockronchcs have hccn descr~hcd, hut onl) ahout 50 species o f thcln arc considered as

L 1 Association of cockroaches with human pa/lzogens

\ ~ ~ ~ I I > I I S pathogentc ~rfanisniz I I J \ c hecn as\<>ciatcd u i t h cochroaclies. Thcsc include pollo~n)cllil?, \ iruscs. bacter ia . i u n g ~ . p r o t o f o a a n d heltninth\. l 'hese organistiis ha le ,,lien been isolated f iom ficld-uli- Icctcd cochroachc\ Roih 8; Wlll~s

pests. Most ~ i l t h e m arc round In- I (1957. 1900) puhllshcd t \ ~ o anno- hahltinp the grour~d o f rain forest\ tated lisra oi'the hlotic ass~cia t ion and cal c\ (('ochran 1 Y X 2 ) 6 rpL.u '., fiOm 16 bnCierlopoiera ilart. h pL.,, jiiicd <I(- c ~ ~ e l r o d c h c s \\ ith rntcroi~rgali- Y p /torn cl~ekrooclii~.~. isms in 111onograp11 ~ b r m . Three species o f d o n ~ ~ c ~ l l a r y cock- - -- -

roaches of cosn~opol i t ;~n impor- The p o l i o m y c l ~ t ~ s \ ~ r u s has heen 1;lnce are th~~(icrlllali cockrliach (61/1111~//(1~~rmll~i(.u), thC. Ameri- isolated l i ~ l n lield-collcc[cd Gertnen and ,4n1erican cockroache5 can cockroach (Po-ip/iinri~r t~nreririrna) and the Oriental cr)cL- (Do\\ 1955: Sy\erton ct al. 1952). :I .;tudy e o ~ l d ~ ~ c t e d by Tarshi, r o ~ c h (B/ulr[r oricnrc~lis ). Out of these three speclcs, the Ciennan ( I 962) pm, ided a nlolc concrete c\ ~d~~~~ ofcockrc,ac~les being a cockruach is prohahly the most imponant pest cockroach in nlan! mechanic;ll, ec[orot.hu~n:lll dise;lac. It1 tI1;lt \\hlcll \,as done pans o f [he \rorld duc to its high reproductive potential (Rchll ill 582 house, In LOS Angslca. ('alilbmia (ol'tvl~icli Y 5 ? o \\rrL. badly 1915). In thc Southcasl As~ar i countries. the A n i c l l c ~ n cockroach i n jested \\ith eockroaellTj), tile : I u ~ ~ l o r d e l l l , ~ l l , ~ l a ~ e ~ a positl , 15 theprcd<~l~r~nant spccic\ in dotnicilcs (Oothuman el al. 1'184; Yap relation het\veen ~ n f c ~ t i o u s hepatitis case\ and eoekriiach pop~lla- r i a l . 1991: Lee el al. 199.;). While the Gcrnlan cockroach arc no1 lion i , \ c r a p e r i o d o f t ~ l n c , present in houselliilds in this region. they are of great imponancc lo the pest control ~ndustries due ti1 their presence in hotels ~ n d ~ a n q liolatlons ( ~ f hacterta haye heel1 done ,I" c,jchmaches. TO

li~od handi~ngoutlcls ( Yapeta l 19'41; Leeelai. 1993) A question- dare, 36 s p c c ~ c s Sroln 16 haclcria genera h a \ c been isolaled lio111 nalre w n e y conducted 111 I'enang, Malayzia in 11)')5 rc\ealed that field collecled cnchroachcs hi^ I ) Manr of these l l ~ e householder5 $cored cockroaches a.; the most imponan1 h o u s e trapped ~n places such 35 h o s p ~ t a l ~ . Sc~od manutactur- I~old pest after mosquitoes 1 1 11 I Yap 6 CY Lee, unpuhli\hcd data!. ing pl:~nt5. zchools. rcstauranls. ctc Com\\ell 6 hlcndes ( I'IX I I

reponcd a shocking findills ill tlie or~enta l cochroach (B. ~~r.ic~nro/r.r) Lalcl!. thcrc ha> heen a gro\slng a\varcness of the health threats s h e r e they i so~alcd 1 8 species <if h3~1cr i3 /~Sc~lli/O,ll ,~nil, pi~\cil hy cockro;lches IL? I~umanh. Various pathogenic orgenisnlk oevuginos i~ , C l o , s ~ r i t / ~ ~ , n ~ l ~ ~ r / t l ~ l ~ ~ l l > . Y ~ ~ I ~ I / I J ~ / ~ C ~ ~ , <.liv o/h!,.$, ha\ hccn associated si lth cochroachcs. In additloti, (here has alzo K/ehsji.//a r,t~rr,yenes. ?LC.) in lield-~.ollccted ,-ockroaclles fro,,, 40 hccn numcrouc repon> on rhe allcrgy and asthma prohlrms caused prelnises ~n IIK O n the otherI1:lnd. Kuegcr6; Olson 1 I'Joq) isolated hy cockroaches. This hriel.rc\ ieu sumnlarizes the human health- . s , ~ / I I I , J ~ ~ / / u U , ~ ~ I / I I ~ , .Y. ~ I . O I J I C ~ , ~ ~ I I V ~ and ,YI<,,I/II / o ~ ~ o c ~ ~ i i . ~ t71ive1,.5 related p r < ~ h l c ~ n s caused b) cockroaches. liom morc than 6000 specimens trapped l'rom 14 cities through the

IC'hot makes cockroaches an obnosious insect pest?

\lo\[ dornlc~llary cockrt>aches hnsc ilddpted to live In human dwell- ings. ( '~~chroaches usu;~ll! are found in the kitchen arcas here li>t,d and \\:itcr a le read:l) ;I\ ailable, lofether u i th the pl-esencc ol n \\arm and nn,iul cn\Irontncnl. Their hahlt olforaging i r ~ , ~ i i one place io anothcr and rcgurgit:~nng come ofiheir partially dlpcated h ( > d ; ~ n d ( l c l i c ~ ~ . ~ l ~ n g \ ~ h ~ l c li.ed~r~: makes them an ~ ~ h i q u l t o u me- chanlcal \ se tor ollirlin;ln disease, Their h o d pietcrcnce is \cr! ( l i \ cr,c. ranging Iron1 Iii~liian sputum and p l ~ l e f r l ~ to the deliciou5

In Malaysia. Rampal et dl (1043) ~ h ~ ~ l a t e d I 4 spectci o f bacterial pathogcl~s lrotn the inte\t~nal tracts o f \ ;lrlnus s p e c ~ c \ 01- e ~ e h - roaches trapped from L~tchen\ of l i \ in: prernl\cs and nard.;. kitch- cn\ and slorcs In a Ih~spiti~l. In 3 c o n i p i ~ ~ i ~ o n ? t ~ ~ d y . 22 S ~ C L I C C of bacteria, includil~g pathoscnic ;and polentiall) p;~tIiogeni\: \pcclcs such ;I> .S/~ipe//~r /~oi .~ l i i , .S-. (11 w,~ic,~iuc,, .SO/,II,III~~//~I IJJ I />~, ,~ , , I~~II ,>I , K / e l ~ ~ ~ ~ ~ / / i i o ~ v i o c ~ ~ . K , > : ~ ~ L V J < W and .Y~vrurio t11<nc ',><,L,,I., \ \ere IS<>- Inred t'rcin~ cock~oache\ trapped liom bur p;~cdiatnc \\.~rds (O~i t l iun~at~ el al. ILIXY1 (ia~isod.1 S. Fish ( IC)Xi) puhlishcd Inati! intsre\llng

M E D I C A L M I C R O B 1 O L . O G Y

electron micrographs showing the adhesion of pathogenic bacte- ria on the legs of cockroaches.

On cockroach association with fungi, Fuch (1976) found 27 species of fungi on the exocuticle and 13 species in the gut of 180 German cockroaches, collected from 8 kitchens in Koblenz, Germany. These fungi included dermatophytic and toxin-producing species such as Aspergill7r.r, Trichoderma, Cladospor ium, ~ u s a r i u m , Penicillium and Alternaria. About 15 species of fungi have been isolated from cockroaches (Table 2).

Many non-pathogenic protozoans have also been isolated from cockroaches. However, only four of them are pathogenic to verte- brates, i.e., Entamoeba histolytica, Giardia intestinalis, Toxoplasma gondii (through experimental evidence) and Trichomonas honiinis (Roth & Willis 1957; Wallace 1972). (Editor's note: Blastocystis species vety similar in morphology to B. hominis was isolated in K of 10 cockrouches, suggesting that cockroaches may be a vec- ror in the transmission of this protozoan parasite (Zaman et al, 1993) )

The helminths constitute the second largest group of pathogenic organisms which are mechanically transmitted by cockroaches (Roth & Willis 1957; 1960). Eggs of seven helminth species have been found naturally in cockroaches, whereas eggs of another five spe- cies passed through the guts of cockroaches unharmed and ap- peared in the cockroach faeces. A list on some helminths which have been isolated naturally from cockroaches is shown in Table 3.

A study conducted in Penang, Malaysia on the nematode abun- dance in the American cockroach (Periplaneta americana) demontrated that 98% of the field-collected cockroaches (n = 150) were infected. Of these, 65.8%, 28.40i0 and 57.4% were infected with Hanlmerschmidtiella diesingi, Leidynema appendiczrlata and Thelastoma malaysiense, respectively (Anuar 1987). Two other studies showed that M o n i l ~ f o r m i s ~mon i l i f o rmi s , an acanthocephalan, is a common parasite in the American cockroach (Anuar & Paran 1976; Oothuman et al. 1985). A female P. americana can harbour more than 300 cystacanths (Oothuman et al. 1985).

Association of cockroaches with allergies and asthma

Inhalants and allergens produced by cockroaches have received much attention recently with the increase in household allergy and asthma problems (Brenner et al. 1991). Allergy is an abnormal re- sponse of the immune system to antigens which results in the release of tissue damaging substances. such as histamines. In cockroach associated allergy, the problem occurs when the immu- nological system becomes sensitized to cockroach allergens. When subjected to subsequent exposures, the immune system will over- react and cause damage to host tissues and organs in the process of neutralizing the proteins (Brenner 1995).

Here is a short summary on how a man develops allergy to cock- roaches. When cockroach proteins (cockroach allergens) enter the circulatory system through inhalation, dermal abrasion or in- gestion, immunoglobulin E (IgE) will be produced and will be at- tached to the epitopes of the proteins. As hypersensitivity occurs, cells in the immunological system will mass-produce IgEs. These antibodies will circulate in the blood-stream. Due to their large

numbers, most of them will bind to mast cells commonly found In the mucosal linings of lungs and sinuses. skin and intestines. When two or more IgEs bind to the same cell, the mast cell will degranulate. releasing histamines and other substances that will cause vascular permeability, vasodilation, bronchocontriction, and disrupt the car- diac electrical pathway. Extreme cases can result in anaphylax~s and death (Brenner 1995)

An estimated 10- 15 million people in the USA are allergic to cock- roaches, according to the National Institute of Health (NIH), USA. Reactions usually ranged from a running nose and skin irritation to difficulty in breathing. In addition, about 50 - 60% of asthmatic and atopic populations demonstrated intense reaction to cockroach ex- tracts, as compared with only about 20% of those who are in the non-atopic group (Kang & Chang 1985). A further study on bron- chial asthmatic patients showed that 76% of them lived in crowded homes which were badly infested with German cockroaches (Kang et al. 1987). Schulaner (I 970) reported that in dwellings where Ger- man cockroach infestations are visible. sensitivity among asthniatic children can reach as high as 80°io.

Association of cockroaches with entomophobia crtrtl other implications on lt uman behaviour

Entomophobia or fear of insects is conlmon, especiall!. among women. Many people find cockroaches disgusting. There is an association in the mind of many people between the presence of cockroaches and a dirty environment. As a result, cockroach infes- tations in households can serve as psychological stressors to the residents. To these people, the mere presence of cockroaches wil I bring on modified behavioural responses. For example. they will avoid going to the kitchen at night or avoid going into the store- room, fearing that they will encounter a foraging cockroach in such places.

In some cases, the presence of cockroaches caused irrational be- haviour in the people exposed. Schrut & Waldron (1963) reported that a family was so distressed by 'bad' infestation of cockroaches in their home, that as a result, they moved to another house. In reality, there was only a low infestation of American cockroaches. This behaviour is known as delusory parasitosis. In this respect. cockroaches are the victims of their reputation !

Other importance of cockroaches

Roth & Willis (1957) reported about 20 cases of cockroaches biting humans while the latter were sleeping. Heiser ( 1936) reported that cockroaches on ships gnawed on the calluses. fingernails and ebe- brows of sleeping sailors. Inlact, a.s a child, the mrthor hitll~c~//'/ii~(/ experienced being bitten by cockrotrches on theliriger.~ tt,hili~ .rlc'c~/,- ing alter going to bed without wushing his hands (hi, hull clr/~!t/ squidsfor supper !)

Cockroaches (P. anlericana and Leucophuru tt7trdcrue) have also been shown to excrete compounds which are either niutagenic 01.

carcinogenic. The compounds excreted, i.e., xanthurenic. kynurenic and 8-hydroxyquinaldic acids. are tryptophan derivatives. The> are present in small, but consistent quantitites in faeces (Mullins & Cochran 1973).

S i n g a p o r e M i c r o b i o l o g i s t

Acknowledgment

I he author would like to thank NL Chong for his constructive criticisms on the draft manuscript .

Anuar KA. 1987. Nematode parasiles of the family Telastomatidae in Periplanela amc~ricana Linn in Penang, Malaysia. 'l'ropical Biomedicine 4: 7 1-72.

Anuar K & Paran '1'1'. 1976. Periplatzrta americana (L.) as intermediate hosr of Monili/ormis moniliformis (Brcrnser) in Penang, Malaysia. South- cast Asian Journal of Tropical Medicine and Public Health 7: 4 15-41 6.

Brenner RJ. 1995. Economics and medical importance of German cock- roaches. pp. 77-92. In Understanding and controlling the German cock- roach (Rust MK, Owens JM & Reierson DA, e d ~ . ) . Oxford University Press, New York.

Brenner RJ, Barnes KC. Helm RM & Williams LW. 1991. Modernized soclety and allergies to arthropods: risks and challenges to entomologists. American Entomologist 37: 143- 155.

Cochran DG. 1982. Cockroaches - Biology and Control. WHOIVBCI 82.576 World Health Organization, Geneva, Switzerland.

Cornwell PB. 1968. The Cockroach. A laboratory insect and an indus- trial pesl. Volume I . tlutchinson, 1,ondon.

Cornwell PB & Mendes MF. 1981. Disease organisms carried by Orien- tal cockroachcs in relation to acceptable standards of hygiene. Interna- tlonal l'esl Control 23: 72-74.

Ilow RP. 1955. A note on domestic cockroaches in South Texas. Journal of Ilconomic F:ntornology 48: 106-1 07.

I'uchs ME4. 1976. Zur Verbreitung humanpathogener und toxinbildender I'ilzc durch Schaben. %. Angew Entomology 82: 89-93 (in German with I'nglish abstract).

Heiser V. 1936. An American doctor's odyssey. WW Norton & Co.. New York.

Kang 13& Chang Jl,. 1985. Allergenic impact of inhaled arthropod mate- rial. Clinical Review ofAllergy 3: 363-375.

Kang B, Johnson J , Jones GS & Kang IJ. 1987. Analysis of indoor environment and asthmatic characteristics of the urban bronchial asthma. Presented at the 3rd Annual Meeting of the Academy of Allergy and Cl~nical Immunology, Washington DC. February 1987.

Lee CY, Chong NL & Yap 141-1. 1993. A study on domiciliary cockroach infestation in I'enang. Malaysia. Journal of Bioscience 4: 95-98.

Mullins DE & Cochran DG. 1973. Tryptophan metabolic excretion by [he American cockroach. Comparative Biochemistry and Physiology 44B: 549-555.

Oolhuman P. Jcffery J , Daud MZ, Rampal L & Shckhar C. 1984. Distri- bulion of different species ofcockroaches in the district of Kelang, Selangor. Journal of Malaysian Society of Health 4: 52-56.

Oothuman P. Jeffery J, Daud MZ, Kampal 1, & Shekhar C. 1985. On a collccrion of acanthocephalan cystacanths in domiciliary cockroachcs from the dislricl of Kclang, Selangor and the Kuala Lumpur Federal Territory.

Journal of the Malaysian Society of llealth 5. 81

Oothuman P, Jeffery .I. Aziz A1 14. i\bu Bakar 1: & Jqathcsan M. 1989. Bacterial pathogens isolatcd from cockroaches rrappcil t'rom paediatric wards in Peninsular Malaysia. I'ransactions oi'rhe Ro! al Socicr! oll'ropical Medicineand Hygienc 83: 133-135.

Rampal L. Oothuman P, JeSfen I . Daud MZ. Shckhar C. Scnan 1'. 1.m KE. Suboh Y & Ahmad %. 1983. Bacterial pathogens from the intrsl~nal tracls of various species of cockroaches. Medical Journal of Mala)sia 38: 101- 107.

Rehn JAG. 1945. Man's uninvited fello\+ t r avc lc r the cockroach. Scie11- tific Monthly 6 1 . 265-276.

Roth LM & Willis ER. 1957. The medical and veterinar! importance of cockroaches. Smithsonian Institute Miscellaneous C:ollection 134: 1 - 147.

Roth LM & Willis ER. 1960. The biotic associations of cockroaches. Smithsonian Institute Miscellaneous Collection 141 : 1-470.

Rueger ME & Olson TA. 1969 Cockroaches (Blattaria) as vectors of food-poisoning and food infect~on organisms. Journal of' Mcd~cal Ento- mology 6: 185-189.

Schrut AH & Waldron WG. 1963. Psychiatric and entomological aspccrs of delusory parasitosis. Journal of American Medical Associalion 186. 429-430.

Schulaner FA. 1970. Sensitivity to cockroaches in three groups of allergic children. Pediatrics45: 465.

Syverton JT. Fischer RG. Smith SA. Dow RP & Schoof 11F. 1951. I-he cockroach as a natural extrahuman source ol'poliomyclitis virus Fcdcral Protection 1 1 : 483.

Tarshis IB. 1962. The cockroach - a ne\r suspect in the spread o f infec- tious hepatitis. American Journal of 'l'ropical Medicinc and Ilygienc I I 705-71 1 .

Wallace GD. 1972. Experimental transmission of To.xoplusmrr gondii b! cockroaches. Journal of Infectious Diseases 126: 545-547.

Yap HH. Chong NL. Loh I'Y. Baha R. Yahaya AM. 1991. Sur \ .q of domiciliary cockroaches in Pcnang. Malaysia. Iournal ofl3iosciencc 2 7 1 - 75.

%aman V, Ng GC, Suresh K. Yap EH. Sing. M. 1993. Isolation of Rlustoc~v.~~is fro171 the cockroach (Dictyoptera Blattidae). Parasitology Kcscarch 79: 73- 74.

The author is currently a Lecturer at the School of Biologlcul Sciences, Universiti Sains Malaj~sia in Penang. His research in- terests are insecticide resisfance, and biology heha\.iour and i,on- trol of household (e structurul itisect pests (cockrou~~hes, ants and termites) in the urban environment.

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M I C R O B I O L O G Y

Table 1: L is t o f pathogenic bacteria species associated w i t h cockroaches (compiled f r o m Roth & W i l l i s 1957; C'ornwcll & 9lendrs 1981; Oothuman r t a l . 1989; Brenner 1995).

Pathogen Associated diseases Alcalrgenes faecalrs Gastroenteritis Bacrllus sub~rlrs Conjunctivitis Bac~llus cereus Food-poisoning Clos~ridium novrr Gas gangrene ('loslridium perfrrngens Food-poisoning Enrerobacrer uerogenes Bacteremia Cscherrchru coli Diarrhoea, wound infection Klebsrella aerogenes Klebsrellu oxyroca Klebsrella ozuenae Klebsrello pneumonrae Pneumonia Mycobac~erirrm leprae Leprosy :Vocardra sp Actinomycetoma Proreus morganir Wound infection Proleus rerrgeri Wound infection Proleus vulgaris Wound infection Proleus mirabilis Gastroenteritis Pseudomonas aerugrnosa Respiratory infections Salmonella bredeny Food poisoning Salmonella boydii Salmonella newporr Food poisoning Salmonella oranienburg Food poisoning Salmonella panama Food poisoning Salmonella paratyphi-B Food poisoning Salntonella ryphi Typhoid Salntonella ryphimurium Food poisoning Salmonella bovis-morbijicansFood poisoning Salmonella bareilly Food poisoning Serra~ra murcescens Food poisoning Shigellu dysenleriae Dysentery S~aphylococcus albus S~aphylococcus aureus Skin infection, infection o f internal organs

Streplococcus faecalis Pneumonia Slreprococcus pyogenes Pneumoni a Vibrro spp. Yersinia pestrs Plague

Cockroach species Periplanelu arnerrcona. Blu/:u orren~ulis Blaberus craniifer, B orren~rrlrs. P an7errcuna Blaberus cranrlfer B. orienlalrs B orienlalis B la~ le l la germanica, P umericana B. orienlalis, B. germunrcu, P, amerrcanu B orienlalis P americana P , americanu Not known B. germanrcu, P. omerrcano. P uuslralas~ae P. americana P. americana P. amerrcana B. cranrijer. B, orienlalis, P. amerrcano P, amerrcana B. craniijer, B. orienlalis, B germanicu, P omerrcano P. americana P, americana P. antericana P. americana P. americana P. americana B, orienlalis B. germanica P. americana P. americana P. americana, B, orrenrulrs. B germunrca B. germanica B. orienlalis B, craniijer, B. orientalis, B. germanicu B. orienralis. B. germanica,P americana B. orienlalrs B. orienlalis B. orienlalis

Table 2 : L i s t o f pathogenic fungi species associated w i t h cockroaches (compi led f rom Roth & W i l l i s 1957; Brenner 1995)

Pathogen Alrernariu sp. Aspergillus niger Aspergrllus Jlavus Aspergillus fumigatis Candida krusei Candrda paraspilosis Candida tropicalis

Cephalosporium Cladosporium sp. Fusarium sp. Georrichum candidum

Mucor sp. Penrcillrum Rhizopus sp. Rhodolorula rubra Trichoderma viride Trichosporon cutaneum

Associated diseases Skin & lung infection Pneumomycosis Mycotic granuloma Pneumomycosis, bronchomycosis Candidiasis of mucosal membranes in infants, skin, respiratory passages, gastrointestinal tract; endocarditis. Facultatively pathogenic,mycetoma Dermatomycosis Otomycosis Chronic bronchitis,, skin & gastrointestinal tract infections Occasional infection of lung and otomycosis Not available Occasional infection o f lung, otomycosis Rare opportunistic infections Rare alimentary toxic aleukia White hair-nodule disease

C o c k r o a c h species Blattella germanica Periplaneta americana. Blatra orientalis B. germanica B, orienlalis B. gerntanica

B. germanica acremonium B. germanica B. germanica B. germanica

B, germanica B. orientalis B. gerntanica B. gerntanica B. gerntanica B. germanica

Tab le 3 : L i s t o f pathogenic helminth species associated w i t h human diseases (compi led f r o m Roth & W i l l i s 1957; B r r n n r r 1995).

Pathogen ~ l n c ~ ~ l o s ~ o m u duadenale .Iscarls lumbrrcordes A.ccarrs sp En~erobirrs vermrculorrs Hj,menolopsis sp .Veculor urnerrcanus Trichuris lrichuriu

Associated diseases Hookworm Giant human roundworm Roundworm Pinworm Tapeworm Hookworm Trichuriasis

Cockroach species Periplunela americono Periplanela americona Blarra orienralis B. orienlalis. B lar~el la gertnunrca P. amerrcana P. umericana B. orrenralis. R. gern7anrca. I' dii~errcana

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