Diagnosing multiple parasitic infections: trypanosomiasis, loiasis and schistosomiasis in a single case

The lymphatic system favours survival of a unique T. brucei population

Trypanosoma brucei colonise and multiply in the blood vasculature, as well as in various organs of the host's body. Lymph nodes have been previously shown to harbour large numbers of parasites, and the lymphatic system has been proposed as a key site that allows T. brucei distribution through, and colonization of the mammalian body. However, visualization of host-pathogen interactions in the lymphatic system has never captured dynamic events with high spatial and temporal resolution throughout infection. In our work, we used a mixture of tools including intravital microscopy and ex vivo imaging to study T. brucei distribution in 20 sets of lymph nodes. We demonstrate that lymph node colonization by T. brucei is different across lymph node sets, with the most heavily colonised being the draining lymph nodes of main tissue reservoirs: the gonadal white adipose tissue and pancreas. Moreover, we show that the lymphatic vasculature is a pivotal site for parasite dispersal, and altering this colonization by blocking LYVE-1 is detrimental for parasite survival. Additionally, parasites within the lymphatic vasculature have unique morphological and behavioural characteristics, different to those found in the blood, demonstrating that across both types of vasculature, these environments are physically separated. Finally, we demonstrate that the lymph nodes and the lymphatic vasculature undergo significant alterations during T. brucei infection, resulting in oedema throughout the host's body.

Imported Loa loa filariasis: three cases and a review of cases reported in non-endemic countries in the past 25 years

OBJECTIVES

The aim of this study was to highlight the increasing chance of Western physicians encountering patients (both immigrants and expatriates/travelers) seeking help for loiasis.

METHODS

We describe three cases of imported loiasis observed at two hospitals in Italy and France, and present a review of all previously published cases in the medical literature in the last 25 years (1986-2011). The search was performed using PubMed and Scopus databases using the terms "Loa loa" AND "loiasis".

RESULTS

We reviewed 101 cases of imported loiasis of which 61 (60.4%) were reported from Europe and 31 (30.7%) from the USA. Seventy-five percent of infestations were acquired in three countries: Cameroon, Nigeria, and Gabon. Overall, peripheral blood microfilariae were detected in 61.4% of patients, eosinophilia in 82.1%, eye worm migration in 53.5%, and Calabar swellings in 41.6%. However, Calabar swellings and eosinophilia were more common among expatriates/travelers, whereas African immigrants were more likely to have microfilaremia. Eye worm migration was observed in a similar proportion in the two groups. Only 35 patients (including the three described here) underwent clinical follow-up for a median period of 10.5 months (range 1-84 months); clinical relapse occurred in three of these patients and persistence or reappearance of blood microfilaria in another two.

CONCLUSIONS

Due to increasing travel and the migration of people from the endemic countries of West Africa to Europe and the USA, we speculate on the possible emergence of loiasis. Western physicians should be aware of the typical (eye worm migration and Calabar swellings) as well as unusual clinical presentations.

Prevalence and types of coinfections in sleeping sickness patients in kenya (2000/2009)

The occurrence of coinfections in human African trypanosomiasis (HAT) patients was investigated using a retrospective data of hospital records at the National Sleeping Sickness Referral Hospital in Alupe, Kenya. A total of 31 patients, 19 males and 12 females, were diagnosed with HAT between the years 2000 and 2009. The observed co-infections included malaria (100%), helminthosis (64.5%), typhoid (22.5%), urinary tract infections (16.1%), HIV (12.9%), and tuberculosis (3.2%). The species of helminthes observed included Ancylostoma duodenale (38.7%), Ascaris lumbricoides (45.7%), Strongyloides stercoralis (9.7%), and Taenia spp. (3.2%). The patients were also infected with Entamoeba spp. (32.3%) and Trichomonas hominis (22.6%) protozoan parasites. The main clinical signs observed at the point of admission included headache (74.2%), fever (48.4%), sleep disorders (45.2%), and general body pain (41.9%). The HAT patients were treated with suramin (early stage, 9/31) and melarsoprol (late stage, 22/31). In conclusion, the study has shown that HAT patients have multiple co-infections which may influence the disease pathogenesis and complicate management of HAT.

Case report: Loiasis with peripheral nerve involvement and spleen lesions

Loiasis, which is caused by the filarial nematode Loa loa, affects millions of persons living in the rainforest areas and savannah regions of central Africa. Typical manifestations are calabar swellings and the eyeworm. We report a case of loiasis with unusual clinical complications: a peripheral neuropathy and focal hypo-echogenic lesions of the spleen, which disappeared after treatment with albendazole and ivermectin. The literature reports that L. loa infection can be associated with various manifestations, some of them being serious. More information is needed to better characterize the protean manifestations of the disease in loiasis-endemic areas to evaluate the true incidence of loiasis.

The natural progression of Gambiense sleeping sickness: what is the evidence?

Gambiense human African trypanosomiasis (HAT, sleeping sickness) is widely assumed to be 100% pathogenic and fatal. However, reports to the contrary exist, and human trypano-tolerance has been postulated. Furthermore, there is uncertainty about the actual duration of both stage 1 and stage 2 infection, particularly with respect to how long a patient remains infectious. Understanding such basic parameters of HAT infection is essential for optimising control strategies based on case detection. We considered the potential existence and relevance of human trypano-tolerance, and explored the duration of infectiousness, through a review of published evidence on the natural progression of gambiense HAT in the absence of treatment, and biological considerations. Published reports indicate that most gambiense HAT cases are fatal if untreated. Self-resolving and asymptomatic chronic infections probably constitute a minority if they do indeed exist. Chronic carriage, however, deserves further study, as it could seed renewed epidemics after control programmes cease.

African trypanosomiasis gambiense, Italy

African trypanosomiasis caused by Trypanosoma brucei gambiense has not been reported in Italy. We report 2 cases diagnosed in the summer of 2004. Theses cases suggest an increased risk for expatriates working in trypanosomiasis-endemic countries. Travel medicine clinics should be increasingly aware of this potentially fatal disease.

Acute progressive bilateral carpal tunnel syndrome after upper respiratory tract infection

This report describes the case of a 32-year-old male presenting with acute progressive bilateral carpal tunnel syndrome after a benign upper respiratory tract infection. Serial nerve conduction studies confirmed progressive entrapment of the median nerves in the carpal tunnel to the point of axonal damage. Surgical decompression relieved the entrapment, and nerve conduction studies improved.

The challenge of Trypanosoma brucei gambiense sleeping sickness diagnosis outside Africa

Sleeping sickness is a lethal African disease caused by parasites of the Trypanosoma brucei subspecies, which is transmitted by tsetse flies. Occasionally, patients are reported outside Africa. Diagnosis of such imported cases can be problematic when the infection is due to Trypanosoma brucei gambiense, the chronic form of sleeping sickness found in west and central Africa. The low number of trypanosomes in the blood and the non-specific, variable symptoms make the diagnosis difficult, particularly when the index of suspicion is low. When the trypanosomes have penetrated into the central nervous system, neuropathological signs become apparent but even at this stage, misdiagnosis is frequent. Rapid and correct diagnosis of sleeping sickness can avoid inappropriate or delayed treatment and even death of the patient. In this article, an overview on diagnosis of imported cases of T b gambiense sleeping sickness is given, and possible pitfalls in the diagnostic process are highlighted. Bioclinical parameters that should raise the suspicion of sleeping sickness in a patient who has been in west or central Africa are discussed. Techniques for diagnosis are reviewed. A clinician suspecting sleeping sickness should contact a national reference centre for tropical medicine in his or her country, or the WHO, Geneva, Switzerland, or the Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA, for clinical consultation and provision of specific diagnostic tests. Appropriate drugs for sleeping sickness treatment are also provided by WHO and the CDC.

Acute carpal tunnel syndrome due to filarial infection

A case of acute carpal tunnel syndrome (CTS) due to filarial infection is reported in a resident of Newfoundland, Canada. The patient presented with classical symptoms and signs of acute CTS and a filarial worm was identified in synovial tissue removed during surgery that was morphologically consistent with the genus Brugia. Antifilarial antibodies were present in serum. Surgical removal of the infected tissue, without administration of antifilarial drugs, proved adequate in eradicating the infection and a subsequent serum sample was negative for antifilarial antibodies. The patient remains asymptomatic more than two years after surgery. This case is unusual in its clinical presentation and geographic location.

Thrombosis of the ulnar veins--an unusual manifestation of Loa loa filariasis

A 49-y-old male, who had travelled in Central Africa, was admitted to hospital with oedema of the right forearm. He was diagnosed as having thrombosis of the ulnar veins. Subsequently eosinophilia and positive serology for filariae established the aetiologic agent as Loa loa. The patient received antithrombotic and antiparasitic therapy. This is, to our knowledge, the first reported case of thrombosis of the ulnar veins associated with Loa loa.