Dynamic changes in biomarker profiles associated with clinical and subclinical tuberculosis in a high transmission setting: a four-year follow-up study

Mycobacterium tuberculosis (MTB) is a slow growing bacterium. Therefore, the immune responses associated with resolution of infection or development of disease post-exposure may take several months to evolve. We have carried out a prospective longitudinal study in a high TB transmission setting to determine the evolution of biomarkers in a recently exposed household contact (HC = 77) and their respective sputum positive index cases (TB = 17). Mycobacterium-induced cytokines [interferon-gamma (IFN-gamma), tumour necrosis factor-alpha, interleukin-6 (IL-6) and IL-10)] were assessed in whole blood cultures and immunoglobulin G (IgG1) antibodies in plasma. When compared with non-exposed community controls (endemic controls = 59) the HC group at intake showed changes in biomarkers commensurate with recent exposure. The HC group showed significant increases in IFN-gamma between 0 and 6 months (paired t-test; P = 0.001) and IL-0 between 6 and 12 months (P = 0.001), most likely reflecting the role of these cytokines in resolution and immune recovery from infection as this HC cohort remained symptom-free for 4 years without prophylactic treatment. When the TB group post-treatment was compared with the HC group, the best discriminators (ANOVA; repeated measures) were IL-10 responses at 0 (P = 0.004) and 6 months (P = 0.001) and IgG1 at 6 (P = 0.004) and 12 months (P = 0.014) with a 3-4 fold higher responses in the TB group. Therefore, within each group, biomarkers show unique profile of responses. These studies highlighted the importance of assessing multiple biomarkers in longitudinal studies for providing better understanding of protective biomarker profiles associated with resolution of clinical and subclinical infections in TB.

Function preservation with multimodality treatment in locally advanced oral tongue cancer

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Background: Total or near total glossectomy with postoperative radiation is a standard treatment option for locally advanced squamous cell carcinoma oral tongue (LASCCOT). However, the procedure is controversial due to dismal cure rates and major functional deficits that impact on speech, deglutition and quality of life. We evaluated function preservation and survival outcome in LASCCOT treated with induction chemotherapy, limited surgery, and postoperative radiation/chemoradiation. Methods: We retrospectively identified 15 patients with LASCCOT treated with induction chemotherapy, limited surgery and postoperative radiation/chemoradiation at our institution between 04/07 - 04–08. M67%:F33% median age 50 years. Pretreatment AJCC stage as assessed on MRI was T2N+ (tumour crossing midline) 13%, T3N0 20%, T3N+ 47%, and T4N+ 20%. Prior to surgery induction chemotherapy, consisting of cisplatin 75 mg/m2 day 1 and gemcitabine 1 mg/m2 day 1 and 8 every three weeks for 2 cycles was given. Four to six weeks following second cycle of chemotherapy local excision of residual primary tumor with ipsilateral modified neck dissection was performed. Postoperative radiation dose was 60Gy/30 fractions. Post therapy pathological stage was ypT0N0 20%, ypT1N0 20%, ypT1N+ 40%, ypT2N+ 13%, and ypT3N+ 7%. Patients with ypN+ disease received concomitant 3 weekly cisplatin 75 mg/m2 with radiation. Results: Overall and disease free survival at 20 months was 60%. Twelve patients (80%) are alive and 3 patients (20%) have died of disease at 9, 14 and 14 months (locoregional failure 1 and distant metastasis 2 patients). In patients alive without disease assessment of deglutition and speech at the time of last follow up showed all patients on full oral diet with spontaneous intelligible speech. Conclusions: Multimodality treatment with induction chemotherapy, limited surgery and post operative radiation/chemoradiation may allow selected LASCCOT patients to avoid morbid surgery and preserve tongue function without compromising survival. This approach merits further investigation in clinical trials.

No significant financial relationships to disclose.

Neoadjuvant chemotherapy followed by radiotherapy or chemoradiation for locally advanced nasal and paranasal sinus tumors

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Background: The treatment of locally advanced nasal and paranasal sinus tumors is controversial. The disease is chemosensitive and there is increasing interest in the use of chemotherapy with radiation in this group of patients. Our aim was to determine survival in patients with locally advanced nasal and paranasal sinus tumors treated with neoadjuvant chemotherapy followed by radiotherapy or chemoradiation (RT/CRT). Methods: Between August 2005 and August 2008, 21 patients with AJCC stage III or IV nasal and paranasal sinus tumors were treated with neoadjuvant chemotherapy followed by RT/CRT in our institution. There were 15 males and 6 females (M 71%:F 29%) with a median age of 49 years (range 19 - 70 years). Site of disease was nasal cavity 33% (7), ethamoid sinus 43% (9), maxillary antrum 19% (4), and frontal sinus in 5% (1) of patients. Histopathological diagnosis was squamous cell carcinoma 43% (9), undifferentiated carcinoma 29% (6), adenocarcinoma 19% (4), esthesioneuroblastoma in 9% (2) of patients. Induction chemotherapy consisted of cisplatin 75 mg / metre2 day 1 and gemcitabine 1 gm / metre2 day 1 and 8 every three weeks. Eighty-five percent (18/21) received 2 cycles of neoadjuvant chemotherapy (range 1–4 cycles) prior to radiotherapy. Radiotherapy dose was 54 Gy - 70 Gy (median radiation dose 66 Gy). Fifty-seven percent (12/21) received concomitant cisplatin with radiotherapy. Results: Response to neoadjuvant chemotherapy; complete in 19% (4), partial in 67% (14), no response/progression 14% (3). Following RT/CRT 86% (18/21) had complete regression of disease. Thirty-three percent (7/21) have failed treatment (local 3, regional 2, and distant metastasis in 2 patients). Among treatment failures 2 patients were successfully salvaged; surgery for local recurrence in one patient and in the other case radiation was given for regional recurrence. Disease free and overall survival at 40 months was 52% and 63%, respectively. Conclusions: Gemcitabine cisplatin chemotherapy has good activity in nasal and paranasal sinus tumors. In combination with RT/CRT survival rates are encouraging and the approach merits further investigations in clinical trials.

No significant financial relationships to disclose.

Primary squamous cell carcinoma of the oral cavity at presentation in Pakistan

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Background: Squamous cell carcinoma of oral cavity (SCCOC) is characterized by marked geographical differences in frequency and site distribution. Pakistan is situated within the high risk zone on the global oral cancer map. However, no reliable data exists on oral cancer in this area. Our aim was to determine clinicopathological features and patterns at presentation of primary SCCOC in a comprehensive cancer centre in Pakistan. Methods: Demographic, risk factors, pathological and AJCC staging data for SCCOC treated at Shaukat Khanum Memorial Hospital for the period November 2003-October 2008 were obtained from the head and neck unit database. Results: The database identified 666 patients with biopsy proven primary SCCOC. Mean age was 53 years (range 12 - 90 years). Male (428): Female (238) ratio was M64%:F36%. The occurrence of major risk factors for oral cancer specifically smoking, betel quid chewing, naswar (smokeless tobacco) and alcohol use in males (428) was 45% (193), 28% (118), 29% (126), 3% (13), and in females (238) was 8% (20), 29% (68), 13% (30), 0% (0), respectively. Thirty-eight percent (411/666) had no association with tobacco, betel quid or alcohol use. Subsite within oral cavity; anterior tongue 41.1% (274), buccal mucosa 26.6% (177), lower gingival and alveolus 19.5% (130), upper gingival and alveolus 4.1% (27), lips 3.6% (24), retromolar trigone 2.9% (19), hard palate 1.7% (11), and floor mouth 0.6 (4). Broder's/World Health Organization histological grade; grade I 52% (334), grade II 34% (226), grade III 7% (49), and unknown 5% (36). According to AJCC 2002 system 0.2% (1), 10.8% (72), 12.2% (81), 13.2% (88), and 63.7% (420) had stage 0, I, II, III, and IV, respectively. Conclusions: Approximately 80% of patients with primary SCCOC present with stage III or IV disease with anterior tongue as the most common subsite in our hospital. While tobacco and betel quid chewing can be attributed to development of SCCOC in a significant proportion of patients, nearly 38% are unlinked to typical risks factors suggesting other environmental and genetic agents as etiological factors in this region.

No significant financial relationships to disclose.

Relationship between circulating levels of IFN-gamma, IL-10, CXCL9 and CCL2 in pulmonary and extrapulmonary tuberculosis is dependent on disease severity

Protection against Mycobacterium tuberculosis infection is dependent on T cell and macrophage activation regulated by cytokines. Cytokines and chemokines produced at disease sites may be released into circulation. Data available on circulating cytokines in tuberculosis (TB) is mostly on pulmonary TB (PTB) with limited information on extrapulmonary disease (EPul-TB). We measured interferon-gamma (IFN-gamma), interkeukin-10 (IL-10), CXCL9 and CCL2 in sera of patients (n = 80) including; PTB (n = 42), EPul-TB (n = 38) and BCG vaccinated healthy endemic controls (EC, n = 42). EPul-TB patients comprised those with less severe (LNTB) or severe (SevTB) disease. Serum IFN-gamma, IL-10 and CXCL9 levels were significantly greater while CCL2 was reduced in TB patients as compared with EC. IFN-gamma was significantly greater in PTB as compared with LNTB (P = 0.002) and SevTB (P = 0.029). CXCL9 was greater in PTB as compared with LNTB (P = 0.009). In contrast, CCL2 levels were reduced in PTB as compared with LNTB (P = 0.021) and SevTB (P = 0.024). A Spearman's rank correlation analysis determined a positive association between IFN-gamma and IL-10 (rho = 0.473, P = 0.002) and IFN-gamma and CXCL9 (rho = 0.403, P = 0.008) in the PTB group. However, in SevTB, only IFN-gamma and CXCL9 were positively associated (rho = 0.529, P = 0.016). Systemic levels of cytokines are reflective of local responses at disease sites. Therefore, our data suggests that in PTB increased IFN-gamma and CXCL9 balanced by IL-10 may result in a more effective cell mediated response in the host. However, elevated inflammatory chemokines CXCL9 and CCL2 in severe EPul-TB without concomitant down modulatory cytokines may exacerbate disease related pathology and hamper restriction of M. tuberculosis infection.

Does physician bias affect the quality of care they deliver? Evidence in the care of sexually transmitted infections

BACKGROUND

Primary care providers are well placed to control the spread of sexually transmitted infections (STI); however, care is likely to be influenced by their attitudes and beliefs. The present study investigates the relationship between general practitioner's (GP) self-reported level of comfort in dealing with patients with STI and the care they deliver.

METHODS

A postal survey was conducted using a stratified random sample of 15% of GPs practising in New South Wales, Australia, to assess practitioners' management of STI. A total of 409 GPs participated in the study yielding a response rate of 45.4%.

RESULTS

Although over two-thirds (69-72%) of GPs were comfortable in managing STI in heterosexual or young patients, fewer than half (40-46%) felt comfortable caring for patients who were sex workers, indigenous, people who inject drugs, gay or lesbian. Practitioners who were comfortable were more likely to offer sexual risk assessment, safe-sex counselling, and were less likely to report limited ability to influence patients' risk behaviours. Practitioner discomfort was positively associated with reporting constraints in sexual history-taking and the need for training in sexual health.

CONCLUSIONS

Practitioners' care and support for patients with STI are influenced by their inexperience, lack of skills and/or attitudes. The reasons for GP discomfort in managing STI patients need further exploration as does its impact on patient care.

Cisplatin plus gemcitabine (GC) as induction chemotherapy in locally advanced head and neck cancer (HANC)

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Background: Cisplatin/infusional 5-fluorouracil chemotherapy is routinely administered as standard induction chemotherapy in advanced HANC. However, the optimum treatment remains to be defined. Gemcitabine is an active agent in HANC and few studies have evaluated induction GC in HANC. We have explored the activity and toxicity of GC as induction treatment in HANC and report the results. Methods: From August 2005 to September 2006, 55 patients with locally advanced HANC had induction chemotherapy with GC at Shaukat Khanum Memorial Cancer Hospital and Research Centre. We reviewed the medical records and prospectively collected data to determine activity and toxicity of induction GC. M:F ratio was 64%:36% with a median age of 50 years (range 19–80). All patients had histologically confirmed squamous cell carcinoma. The site of disease was nasopharynx, paranasal sinuses, oral cavity, oropharynx, larynx and hyopharynx in 4% (2), 11% (6), 51% (21), 2% (1), 11% (6) and 22% (11) respectively. According to AJCC staging 7% (4) had stage III and 93% (51) had stage IVa/IVb disease (T3N0 7%, T3N+ 2%, T4N0 38% and T4N+ 53%). Induction chemotherapy consisted of 2 cycles of cisplatin 75 mg/m2 day 1 and gemcitabine 1000 mg/m2 day 1 and 8 with treatment repeated three weekly. Fifty-three (94%) patients received 2 cycles as planned. Toxicity was scored after each cycle according to the NCI.CTC criteria. Response was assessed following completion of induction chemotherapy by clinical examination/MRI scan. Results: All patients were available for assessment of toxicity and response. A total of 111 cycles were delivered. The response rates are: complete 24% (13), partial 62% (34), no response 7% (4) and progression 7% (4). The overall response rate was 86% (complete 24%, partial 62%). No treatment related deaths occurred. Haematological G3/G4 toxicity included neutropenia (13%/7%) and thrombocytopenia (5%/0%). The non-haematological toxicity observed (nausea, vomiting and diarrhoea) was only G1/G2. Conclusions: GC is well tolerated with low toxicity and high anti tumour activity as neoadjuvant chemotherapy treatment in squamous cell head and neck cancer. Combination GC arm should be included in future trials.

No significant financial relationships to disclose.

Comparative features and outcomes of malaria at a tertiary care hospital in Karachi, Pakistan

OBJECTIVES

A comparison of clinical and laboratory features, diagnostic methods, drug treatment, and outcomes for patients hospitalized with malaria by Plasmodium species.

METHODS

Records of 521 patients hospitalized during the four and half-year study period were analyzed.

RESULTS

Infections were caused by Plasmodium vivax (51.8%), Plasmodium falciparum (46.5%), P. vivax plus P. falciparum (1.3%), and Plasmodium malariae (0.4%). Vomiting (odds ratio (OR)=1.86, p=0.001) and abdominal pain (OR=1.60, p=0.024) occurred more frequently in patients infected with P. falciparum compared to P. vivax; this was also the case for hepatomegaly, splenomegaly and jaundice. Low hemoglobin levels were common but were significantly lower with P. falciparum, and creatinine levels were significantly higher with P. falciparum. Treatment regimens consisted of single drug therapy (61.5%), appropriate combination therapy (15.8%), and inappropriate combination therapy (22.7%). Antimalarials given alone included chloroquine (38.7%), quinine (19%) and doxycycline (1.5%). The overall mortality was 1.7% (n=9) and nearly 56% of patients developed disease complications, most commonly thrombocytopenia (36.4%), anemia (23.4%), and thrombocytopenia plus anemia (32.7%).

CONCLUSIONS

Despite resistance, chloroquine was prescribed in patients with malaria requiring hospitalization. We found a high proportion of single antimalarial drug use as well as inappropriate combination therapy (22.7%), and inadequate use of primaquine terminal prophylaxis. Physicians need to be acquainted with malaria treatment guidelines in an endemic zone.

Phytoestrogens levels determination in the cord blood from Malaysia rural and urban populations

This study is a result of an analysis of free and conjugated phytoestrogens daidzein, genistein, daidzin, genistin and coumesterol in human cord blood plasma using LCMS. Cord blood was collected from urban and rural populations of Malaysia (n=300) to establish a simple preliminary database on the levels of the analyzed compounds in the collected samples. The study also aimed to look at the levels of phytoestrogens in babies during birth as this may have a profound effect on the developmental process. The sample clean up was carried out by solid-phase extraction using C18 column and passed through DEAE sephadex gel before analysis by LCMS. The mean concentrations of total phytoestrogens were daidzein (1.4+/-2.9 ng/ml), genistein (3.7+/-2.8 ng/ml), daidzin (3.5+/-3.1 ng/ml), genistin (19.5+/-4.2 ng/ml) and coumesterol (3.3+/-3.3 ng/ml). Distribution of phytoestrogen was found to be higher in samples collected from rural areas compared to that of urban areas.

The profile and incidence of cancer in Down syndrome

BACKGROUND

Down syndrome is one of the commonest causes of intellectual disability. As life expectancy improves with early and more intensive surgical and medical treatments, people with the disorder are more likely to exhibit classic morbidity and mortality patterns and be diagnosed with diseases such as cancer.

METHODS

A profile of cancer cases among people with Down syndrome has been compiled, based on the analysis of a linked data set that included information from the Disability Services Commission of Western Australian and the State Cancer Registry.

RESULTS AND CONCLUSIONS

Although the total age- and sex-standardized incidence ratios (SIRs) for people with Down syndrome were similar to that for the general population, SIRs for leukaemia were significantly higher while the incidence of certain other types of cancers was reduced. Overall, there was a lower incidence of solid tumours in Down syndrome, possibly reflecting the age profile of the study cohort.

The feasibility of storing ovarian tumor cells on databasing paper: establishing a library of ovarian cancer DNA

The purpose of this study was to assess the feasibility of establishing a library of ovarian cancer nucleic acids using paper matrix by: 1) confirming the stability of DNA stored on paper matrix over a prolonged period of time, 2) determining the amount of genetic material required for storage, and 3) establishing the stability of RNA. Tumor tissue from 66 patients with ovarian cancer was collected intraoperatively, frozen, and dissociated with collagenase and trypsin. A cell suspension was then prepared and spotted onto the paper. The numbers of cells that were stored on the paper were counted using a hemocytometer. The cell suspension was serially diluted and spotted on the paper matrix until the minimum cell number that can be stored and produce a PCR product was determined. PCR, STR genotyping and direct sequencing were performed on tissue stored on the paper matrix. FTA® paper was used as RNA template, and RT PCR converted the RNA to cDNA. Ten to 50 mg of ovarian cancer tissue was stored on FTA® paper. We stored 7 × 104cells on ISOcode® paper and 18 × 104cells on FTA® and obtained extractable DNA. PCR analysis on cards with DNA stored 18 months ago enabled us to establish the stability of DNA after storage. RNA was stable for 6 months when stored on FTA® cards. Since genetic material is extractable from the paper matrices after passage of time, it could be a suitable medium for the storage of genetic material in cancer tissue banks.

Induction chemotherapy with gemcitabine and cisplatin in paranasal sinus tumours

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Background: There is no standard treatment for locally advanced carcinoma of paranasal sinuses. Induction chemotherapy is frequently used to down stage the disease. Surgery, radiotherapy and chemoradiation are all in use to treat the primary following neoadjuvant chemotherapy treatment. Cisplatin and gemcitabine are active agents in head and neck cancers. We evaluated the response of induction chemotherapy with cisplatin and gemcitabine in carcinoma of the paranasal sinuses. Methods: Between August 2005–November 2005, 5 patients with locally advanced carcinoma paranasal sinuses received induction chemotherapy at Shaukat Khanum Cancer Hospital and Research Centre. There were three males and two females, 19 to 65 (median 45) years of age. Three patients had maxillary and 2 patients had ethmoid sinus tumors. Four patients had Stage IVa and 1 patient had Stage IVb disease. All patients had biopsy proven carcinoma. Histologically the tumour was adenocarcinoma in 1 patient and squamous cell carcinoma in 4 patients. Four patients received 2 cycles and 1 patient received 1 cycle of cisplatin 75 mg/m2 day 1 and gemcitabine 1000 mg/m2 day 1 and 8 (repeat day 22) before radical treatment. Response was assessed in all patients with pre and post induction chemotherapy with CT or MRI scan. Results: Overall response rate was 60%. Complete response was seen in one patient and over 50% tumor regression in 2 patients. Disease remained unchanged (no response) in 1 patient. One patient progressed following one cycle and did not receive the second cycle of chemotherapy treatment. The treatment was well tolerated and no grade III or IV toxicity was seen. Conclusions: The combination of gemcitabine and cisplatin in this schedule has low toxicity and significant activity in patients with locally advanced paranasal sinus tumors and is worthy of further study.

No significant financial relationships to disclose.

Tumour thickness as a predictor of neck node metastasis at presentation in early T stage squamous cell carcinoma of oral tongue

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Background: Pakistan has one of the highest incidence of oral cancer in the world. Twenty to thirty percent of the patients have occult neck nodal metastasis at presentation. Elective treatment of neck in early T stage tongue cancer is controversial. The study was conducted to determine the risk of neck node metastasis in patients with T1 or T2 carcinoma tongue on the basis of pathological tumour thickness. Methods: The study group consisted of 20 patients with early T stage carcinoma oral tongue treated at Shaukat Khanum Memorial Hospital and Research Centre between December 2003 - October 2005. There were 10 males and 10 female patients. The median age for the group was 54 years. All patients underwent partial glossectomy with modified neck dissection. Histopathological reports were analysed to stage the patients according to AJCC 2002 system. The glossectomy specimen were serially sectioned to determine histological thickness. Nine patients (45%) had pT1 and 11 patients (55%) had pT2 disease. Patients were divided in to three groups based on tumour thickness; Group I (tumor < or = 3 mm), Group II (> 3 mm but < or = 9 mm) and Group III (> 9 mm). Results: In patients with pT1 lesions there were 2, 3 and 4 patients in group I, II and III respectively. Pathological neck nodal metastasis were seen in 0/2 patients in group I, 1/3 patients in group II and 1/4 in group III. With pT2 lesions there were 0, 4 and 7 patients in group I, II and III respectively. Neck nodal metastasis were found in 3/4 and 3/7 in group II and III patients. The risk of neck node metastasis in patients with tumor thickness more than 3 mm was 28% (2/7 patients) for pT1 patients and 55% (6/11 patients) for patients with pT2 disease. Conclusions: Tumor thickness more than 3 mm in patients with early T stage squamous cell carcinoma oral tongue carries a high risk of neck nodal metastasis. Elective neck treatment should be considered for this group of patients.

No significant financial relationships to disclose.

Elevated serum CCL2 concomitant with a reduced mycobacterium-induced response leads to disease dissemination in leprosy

Mycobacterium leprae and Mycobacterium tuberculosis are successful intracellular pathogens which down regulate host immune responses. T-cell interferon-gamma (IFNgamma) and macrophage tumour necrosis factor-alpha (TNFalpha) activate chemokines such as, C-C chemokine ligand-2 (CCL2) and CCL5, which play a role in granuloma formation. Lepromatous leprosy is characterized by defective granulomas with lowered T-cell- and macrophage-mediated responses. Tuberculosis (TB) can be localized to the lung, whereby discreet granulomas are formed. The role of chemokines in leprosy infections is as yet unclear. We compared chemokine responses in lepromatous leprosy and pulmonary tuberculosis patients. Circulating serum CCL2 was raised while CCL5 was lowered in leprosy, as compared with TB patients and healthy controls. However, both Mycobacterium bovis BCG- (P=0.08) and M. leprae-induced (P=0.05) CCL2 secretion was reduced in leprosy. In leprosy, BCG induced greater CCL2 (P=0.01), TNFalpha (P=0.02) and somewhat greater CCL5 (P=0.08) than M. leprae, while CXCL8 induction was comparable. Overall levels of Mycobacterium-induced CCL2, TNFalpha and CXCL8 were two to threefold lower, and CCL5 was 10-fold lower in leprosy as compared with TB. Reduced inducible CCL2 combined with a lowered TNFalpha response in lepromatous leprosy may contribute to the unrestricted growth and dissemination of mycobacteria found in the disease.

An assessment of intellectual disability among Aboriginal Australians

BACKGROUND

The health and well-being of Indigenous people is a significant global problem, and Aboriginal Australians suffer from a considerably higher burden of disease and lower life expectancy than the non-Indigenous population. Intellectual disability (ID) can further compromise health, but there is little information that documents the prevalence of ID among indigenous populations. This study provides information on ID among the Aboriginal population of Western Australia.

METHODS

The Disability Services Commission (DSC) of Western Australia has maintained a statewide database of people with ID since 1953. Data on people of Aboriginal descent were extracted from the DSC database and linked to two other state-based databases, the Hospital Morbidity Data System and the Deaths Registry, with additional linkage to the National Death Index. The linked data were used to assess the prevalence, survival patterns and causes of death in Aboriginal people with ID.

RESULTS

Although comprising 3.5% of the population, Aboriginal Australians represented 7.4% of all people registered for ID services. The level of ID was assessed as borderline or mild in 40.7% of cases, moderate in 19.9%, severe or profound in 12.1%, but had not been specified in 27.2% cases. Median survival was 55.1 years for men and 64.0 years for women, with a mean age at death (n = 102) of 19.6 years. The leading causes of death were respiratory diseases, diseases of the circulatory system, and accidents.

CONCLUSIONS

The study presents unique population summary data for ID in the Aboriginal community of Western Australia. To provide appropriate prevention and intervention strategies, there is an urgent need for more detailed information on the prevalence and patterns of ID.

Rapid immunochromatography-based detection of mixed-species malaria infection in Pakistan

We report the identification of mixed Plasmodium infections in four recent patients with malaria clinically refractory to empiric chloroquine therapy using the rapid antigen detection kit, NOW ICT Malaria Pf/Pv. A rapid in vitro immunodiagnostic test, the NOW ICT Malaria Pf/Pv test kit was used for the detection of circulating Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) antigens in whole blood. Peripheral blood microscopy confirmed mixed-species infection in all the cases. Thick and thin peripheral blood films were made and stained with Giemsa stain and examined by both hospital laboratory staff and an experienced parasitologist who was blinded to the results of the rapid malarial antigen tests. Four recent patients (all male; mean age, 24 years) with mixed malarial infection were identified. All the subjects were males working for an oil company in a coastal area of Pakistan, and all had been diagnosed presumptively with malaria based on clinical grounds (without microbiologic confirmation), and were treated empirically with chloroquine without clinical response. Semiquantitative malaria counts via microscopy were as follows: P. vivax, scanty (2 patients) and moderate (2 patients); for P. falciparum--scanty (1 patient), moderate (2 patients), and heavy (1 patient). The present case series, although limited by the small number of patients with proven mixed P. falciparum-P. vivax infection, highlights the usefulness of the rapid antigen test in a highly malarious region of Pakistan where chloroquine resistance is prevalent. Although there was full concordance between the results of blood smear microscopy and rapid antigen testing, these techniques are potentially most useful when there is a discrepancy with microscopy findings. Accurate and rapid diagnosis of parasites, particularly in cases of mixed P. falciparum and P. vivax infection, is of immense importance for individual patient management and in reducing the burden of disease, especially in regions of chloroquine resistance.

An experimental model for amoebic abscess production in the cheek pouch of the Syrian golden hamster, Mesocricetus auratus

A new experimental model was developed in hamsters for amoebic abscess caused by Entamoeba histolytica. E. histolytica trophozoites were cultured in a liquid axenic medium, and then injected intradermally into the cheek pouch of the Syrian golden hamster, Mesocricetus auratus. Inoculation consistently resulted in abscess formation at the site in 20 of 22 (91%) study animals. The amoebic nature of the abscesses was confirmed by light microscopy and histopathologic examination. Abscess formation was maximal at day 12 post-inoculation. Potential applications of this simple and reliable model include further elucidation of the pathogenesis of invasive amoebiasis, studies of the host response to amoebae, and in vivo evaluation of chemotherapeutic agents that show in vitro efficacy against E. histolytica.