Baseline TGF-β correlates with protection after immunization with Plasmodium falciparum sporozoites in the Controlled Human Malaria Infection model

BACKGROUND

Here we assessed a possible relationship between baseline TGF-β concentrations and acquisition of sterile immunity after Plasmodium falciparum sporozoite immunization.

METHODS

TGF-β concentrations were determined in samples of 65 malaria-naive volunteers in 4 studies either prior to and after challenge infection, or prior to and after first immunizing infection under chemoprophylaxis with P. falciparum sporozoites.

RESULTS

High baseline TGF-β concentrations were associated with rapid acquisition of sterile protection (p=0.028).

CONCLUSION

Baseline TGF-β concentrations predict the efficiency of acquisition of sterile immunity following sporozoite immunisation and may represent a steady-state regulatory mechanism to keep in check immune systems with a low threshold for activation.

Hypereosinophilia: a diagnostic challenge

Hypereosinophilia encompasses a broad differential diagnosis of atopy/allergic reactions, drug reactions, parasitic infections and paraneoplastic syndromes. Although mostly of limited clinical significance, hypereosinophilia can also be related to hematological malignancies. One has to be aware of the potential for secondary organ damage for example, in the case of hypereosinophilic syndrome. We present three cases with different underlying mechanisms of hypereosinophilia with a brief overview of causes, diagnostic work-up and treatment options.

Recurrent amebic liver abscesses over a 16-year period: a case report

Background

Amebic liver abscess is a rare disease in high-income countries. Recurrence of amebic liver abscess is even rarer with only a few previous reports. Here we present a patient who developed three subsequent amebic liver abscesses over a sixteen-year period.

Case presentation

A Caucasian male developed recurrent amebic liver abscesses, when aged 23, 27 and 39 years. Only on the first occasion did this coincide with a recent visit to the tropics. The patient received adequate treatment during each episode. Possible explanations are persistent asymptomatic carrier state, cysts passage in his family, re-infection or chance.

Conclusion

We describe the unusual case of a healthy male who developed recurrent amebic liver abscesses over a long period despite adequate treatment. Possible pathophysiological explanations are explored.

17D yellow fever vaccine elicits comparable long-term immune responses in healthy individuals and immune-compromised patients

BACKGROUND

The 17D live attenuated yellow fever (YF) vaccine is contra-indicated in immune-compromised individuals and may elicit a suboptimal immunologic response. The aim of this study is to assess whether long-term immune responses against the YF vaccine are impaired in immune-compromised patients.

MATERIALS AND METHODS

Fifteen patients using different immunosuppressive drugs and 30 healthy individuals vaccinated 0-22 years ago were included. The serological response was measured using the plaque reduction neutralization test (PRNT). CD8(+) and CD4(+) T-cell responses were measured following proliferation and re-stimulation with YFV peptide pools. Phenotypic characteristics and cytokine responses of CD8(+) T-cells were determined using class I tetramers.

RESULTS

The geometric mean titre of neutralizing antibodies was not different between the groups (p = 0.77). The presence of YFV-specific CD4(+) and CD8(+) T-cell did not differ between patients and healthy individuals (15/15, 100.0% vs. 29/30, 96.7%, p = 0.475). Time since vaccination correlated negatively with the number of YFV-specific CD8(+) T-cells (r = -0.66, p = 0.0045). Percentages of early-differentiated memory cells increased (r = 0.67, p = 0.017) over time.

CONCLUSION

These results imply that YF vaccination is effective despite certain immunosuppressive drug regimens. An early-differentiated memory-like phenotype persisted, which is associated with effective expansion upon re-encounter with antigen, suggesting a potent memory T-cell pool remains.

Keeping venomous snakes in the Netherlands: a harmless hobby or a public health threat?

OBJECTIVE

To describe the incidence of venomous snakebites and the hospital treatment thereof (if any) amongst private individuals who keep venomous snakes as a hobby.

STRUCTURE

Descriptive study.

METHOD

Private keepers of venomous snakes were invited via the social media Facebook, Hyves, Twitter, Google Plus, Linked In and two large discussion forums to fill in an online questionnaire on a purely voluntary and anonymous basis.

RESULTS

In the period from 1 September 2012 to 31 December 2012, 86 questionnaires were completed by individuals who keep venomous snakes as a hobby. One-third of the venomous snake keepers stated that they had at some point been bitten by a venomous snake. Out of those, two-thirds needed hospital treatment and one-third of those bitten required at least one, sometimes more, doses of antiserum. The chances of being bitten increased the more venomous snakes a person kept. An inventory of the collections of venomous snakes being kept further revealed that no antiserum exists for 16 of the species, including for the most commonly held venomous snake, the coral cobra.

CONCLUSION

Keeping venomous snakes as a hobby is not without danger. Although in the majority of snakebite cases no antiserum had to be administered, there is nevertheless a significant risk of morbidity and sequelae. Preventing snakebites in the first place remains the most important safety measure since there are no antiserums available for a substantial number of venomous snakes.

Two patients with ciguatera toxicity: a seafood poisoning in travellers to (sub) tropical areas

Ciguatera toxicity is a type of seafood poisoning caused by the consumption of ciguatoxic reef fish. We describe two patients with characteristic gastrointestinal and neurological symptoms, both of whom had eaten local seafood. Although mortality is low, morbidity can be considerable due to debilitating symptoms. Most cases originate in the (sub)tropics but due to expanding tourism and fish exportation, it may be encountered in more temperate regions. Treatment is supportive, but some benefit from intravenous mannitol has been reported.

[A patient with fever following a visit to the tropics: tick-borne relapsing fever discovered in a thick blood smear preparation]

A 26-year-old woman presented with a 2-day history of fever peaking to 39 degrees C and cold shivers that developed after a 2-weeks trip to Guatemala and Belize. Prior to the fever the patient had felt symptoms of a common cold and general malaise. Moreover, she complained of generalised myalgia and nausea. She had taken paludrine as a prophylactic against malaria. Borrelia spirochaetes, the pathogen of relapsing fever, were detected in a thick blood smear preparation. On the basis of the anamnesis, geography and specific exposure, the patient had a form of relapsing fever that is transmitted by ticks and not by lice: tick-borne relapsing fever. She was treated with doxycycline, 100 mg b.i.d. for 7 days. She could be discharged home in good condition after 2 days.

[Rocky Mountain spotted fever in an American tourist]

In a 28-year-old male American tourist who presented in the hospital with fever, cold shivers, headache, nausea, myalgia and arthralgia, Rocky Mountain spotted fever was suspected, partly because he came from an endemic region (the state of Georgia). The patient was treated with doxycycline, 100 mg b.i.d.; 9 days after the first appearance of the symptoms, the diagnosis was confirmed by the report of a positive antibody titre against Rickettsia rickettsii. The patient did not have exanthema. He was discharged in good general condition after two weeks of treatment. Rocky Mountain spotted fever, caused by the Gram-negative bacterium R. rickettsii, is a serious rickettsiosis. The disease is seen only sporadically in the Netherlands because the ticks in the Netherlands do not carry the bacterium. The travel history is still not a standard component of the anamnesis and is therefore often forgotten. This can lead to under-diagnosis and delayed treatment of diseases that were formerly limited to the continent. The early recognition and treatment of Rocky Mountain spotted fever is important since delayed treatment is associated with a clear increase in both morbidity and mortality.