in june 2006 , a 74-year - old woman residing in a house in rural new orleans was bothered by a considerable number ( > 50 ) of insect bites .
the woman observed many bugs in the house and showed them to a fumigator , who identified them as triatomines .
an internet search showed the potential for transmission of chagas disease , and the woman sought help from a local health sciences center .
serum samples from both residents of the house were tested for antibodies to t. cruzi at the centers for disease control and prevention ( cdc ) by an indirect fluorescent antibody ( ifa ) test .
samples were also tested at loyola university ( new orleans , la , usa ) and then at cdc . by using an experimental dipstick assay ( trypanosoma detect ; inbios international inc . ,
the woman resident was positive for antibodies to t. cruzi by ifa at dilutions of 1:128 ( 4 weeks after being bitten ) and 1:64 ( 10 weeks after being bitten ) and by dipstick assay .
she was positive for trypanosomes by hemoculture testing with 10 ml blood and coculture in macrophages ( 13 ) 4 months after being bitten .
trypanosomes consistent with t. cruzi were observed in culture beginning on day 46 of culture , and amplification of a t. cruzi  specific 24s rrna gene target confirmed that the isolate was t. cruzi .
the index resident had a history of 5 trips to areas endemic for chagas disease : zacatecas , mexico ( 1970 ) ; cozumel , mexico ( 1990 ) ; belize ( 1991 ) ; guatemala ( 19988 ) ; and costa rica ( 1998 ) , each of < 2 weeks duration , with stays in improved tourist hotels ( less likely to harbor triatomines ) except for the belize trip , which included an 1-week stay in a palm thatch - roofed cabin .
she had not used intravenous drugs or had a blood transfusion or organ transplant , and she is not the daughter of latin american immigrants . except for fatigue ,
cardiac evaluation that included an electrocardiogram showed normal results , and she decided not to take medication .
her residence of 29 years was located on 7.66 acres of bottomland hardwood forest , with many gaps that provided ready access for insects .
a house inspection showed fecal streaks characteristic of triatomines on walls , which were identical to what the patient reported seeing on her nightgown .
twenty dead adult triatomines were collected in the house ( after fumigation ) and in another building on the property that contained a bed .
no nymphs or eggs were found , which suggests that the house had not been colonized .
one live second - stage nymph was collected in a nearby armadillo burrow 50 m from the house .
all triatomines collected were identified as t. sanguisuga according to the key of lent and wygodzinsky ( 6 ) ( figure ) .
because all triatomines except the nymph were dead , pcr was used to determine t. cruzi infection status ( 14 ) .
the last 2 segments of the abdomen were removed from each insect , placed in 200 l 1 pcr buffer ( applied biosystems , foster city , ca , usa ) , boiled for 15 min , and centrifuged .
a total of 5 l of supernatant was amplified in a 50-l reaction ( 3.5 mmol / l mgcl2 and 2 u taq dna polymerase ) .
the primers used anneal to the t. cruzi minicircle dna and were tc3 : 5-ttgaacgcccctcccaaaac-3 and tc4 : 5-gattggggttggtgtaatata-3. the cycling parameters were an initial denaturation step at 94c for 3 min ; 35 cycles at 94c , 55c , and 72c , each for 1 min ; and a 10-min extension at 72c ( programmable thermal controller ; mj research , watertown , ma , usa ) .
twenty percent of the pcr product was subjected to electrophoresis on a 1.8% agarose gel and visualized by uv transillumination after staining with ethidium bromide .
a positive control of 5 l of t. cruzi parasites boiled in 1 pcr buffer and a negative control without the dna template were included with every pcr .
samples that failed to amplify were spiked with 5 l of t. cruzi parasites boiled in 1 pcr buffer and reamplified to ensure that the lack of product was not caused by inhibition of the pcr .
more than half of the triatomines were positive for t. cruzi ( 56% , 10/18 ; 3 failed to amplify ) , with more positive females ( 73% , 8/11 ) than males ( 50% , 3/6 ) .
plasma from the resident dog and 7 other dogs living 1 mile away all tested negative by ifa at cdc .
the assertion that the patient contacted t. cruzi in louisiana is strongly supported by limited travel history to disease - endemic areas and stays mostly in improved housing ( risk for chagas disease transmission is associated with longer residence in disease - endemic areas ) , lack of other risk factors , and large numbers of infected t. sanguisuga in the house .
however , the streaks on her nightgown consistent with triatomine feces indicate exposure , and the parasite could have been introduced into any of her numerous bite wounds .
however , hurricane katrina had hit the area 9 months earlier and increases in domestic infestation with triatomines have been previously reported after a hurricane ( 15 ) .
anecdotally , the armadillo population increased substantially in the months after hurricane katrina , and one can speculate that these hosts supported a larger bug population , who later sought other bloodmeal sources as the armadillo population returned to prestorm levels .
 autochthonous transmission of the chagas disease parasite , trypanosoma cruzi , was detected in a patient in rural new orleans , louisiana . 
 the patient had positive test results from 2 serologic tests and hemoculture . 
 fifty - six percent of 18 triatoma sanguisuga collected from the house of the patient were positive for t. cruzi by pcr . 
The Study
Conclusions