Hello, Welcome to healthcare magic forum. Widal testis positive in typhoid and paratyphoid fever.The treatment for which is antibiotics as it is a bacterial infection. Lumefantrine and Artemether are anti malaria medications and are usually safe and effective in diagnosed case of malaria. There are no known interactions of this medication with Frisium and they both can be given , however ensure that the child has taken his meals prior to the medications to avoid and minimise gastric sideeffects. Please get a confirmed diagnosis before administering any medications as all medications do have some sideeffects and a diagnosed case of typhoid fever will not require anti malaria medicines unless coinfection is suspected as suggested by high fever , low platelet counts and positive blood smear for malarial parasite . Wishing your child a speedy recovery. Regards