Recently, the WHO published a Target Product Profile for a diagnostic test for cutaneous leishmaniasis (CL) and a Roadmap to 2030 for Neglected Tropical Diseases. The documents highlight that existing diagnostic tools for CL are insufficient, whilst setting clear goals for improved sensitivity and reduced cost. The need for species typing in diagnostics is also becoming more pressing with the emergence of drug-resistance, especially of Leishmania tropica. Serological tests are unable to do this, while techniques that can, like PCR, require complex and expensive machinery. Isothermal assays like LAMP offer a promising solution, but more work also remains, as few species-specific LAMP assays have been developed thus far and CL in Ethiopia is particularly neglected. Additionally, since the COVID-19 pandemic, many cheap isothermal diagnostic devices have been produced, which have yet to be tested in the diagnosis of CL. Finally, artificial intelligence presents another avenue for rapid diagnosis by image analysis. In this comprehensive review, we examine the opportunities and challenges inherent to diagnostic development for CL, a priority undertaking that still faces many developmental hurdles.

A detailed kinetic study of hydroxymethylfurfural, lactulose and furosine formation was performed upon heating milk at temperatures between 90 °C and 140 °C. In case of prolonged heating, formation kinetics could be described by a fractional conversion model. Considering only the first phase of the model, kinetics could be simplified to a pseudo-zero order model. A first assessment of kinetic parameters was made by isothermal experiments. Data were analysed using both a 2-step linear and a 1-step non-linear regression method. Only for furosine, did the global 1-step regression approach seem to give better results than the individual 2-step regression approach. Next, the estimated parameters kref and Ea were re-evaluated under non-isothermal conditions by subjecting milk to a time variable temperature profile. Given the complexity of Maillard reaction, it seemed better to estimate kinetic parameters under non-isothermal conditions when using a simplified model. Formation of hydroxymethylfurfural, lactulose and furosine was characterized by an Ea value of 90·2 kJ/mol (k110 °C = 1·2 μmol/l, min), 99·1 kJ/mol (k110 °C = 51·5 mg/l, min) and 88·7 kJ/mol (k110 °C = 16·3 mg/100 g protein, min) respectively. Additionally, 90% joint confidence regions were constructed in order to obtain an accurate representation of the statistical confidence associated with the simultaneously estimated parameters.

A detailed kinetic study of alkaline phosphatase, lactoperoxidase and β-lactoglobulin was carried out in the context of identifying intrinsic time–temperature indicators for controlling the heat processing of milk. The heat inactivation or denaturation of alkaline phosphatase, lactoperoxidase and β-lactoglobulin under isothermal conditions was found to follow first order kinetics. Experimental results were analysed using both a two step linear regression and a one step non-linear regression method. Results obtained using the two statistical techniques were comparable, but the 95% confidence interval for the predicted values was smaller when the one step non-linear regression method was used, indicating its superiority for estimating kinetic parameters. Thermal inactivation of alkaline phosphatase and lactoperoxidase was characterized by z values of 5·3 deg C (D60 °C = 24·6 min) and 4·3 deg C (D71 °C = 38·6 min) respectively. For the denaturation of β-lactoglobulin we found z values of 7·9 deg C (D75 °C = 49·9 min) in the temperature range 70–80 °C and 24·2 deg C (D85 °C = 3·53 min) in the range 83-95 °C. Dref and z were evaluated under dynamic temperature conditions. To estimate the statistical accuracy of the parameters, 90% joint confidence regions were constructed.