Typhoid and dengue coinfection: Case reports

Introduction

Dengue fever is a viral exanthematous febrile illness transmitted to humans by the insect Aedes Aegypti. In the year 2012 alone, India had reported 47,209 cases and 242 deaths from dengue. ¹ Similarly typhoid infection is also an important leading cause of morbidity and mortality worldwide. ² Over 22 million new typhoid cases were reported each year in the world resulting in 200,000 deaths. ³ In the year 2011, 1.06 million cases and 346 deaths from typhoid fever were reported in India. ⁴

Concurrent dengue fever and typhoid fever has been reported rarely in the literature. ⁵ Here, we report two cases; both were treated as outpatients, initially judged as having classical uncomplicated dengue fever, but who were subsequently detected to have coexistent typhoid fever.

Case report 1

A 36-year-old woman presented with fever of 4 days’ duration, associated with chills, body ache, abdominal discomfort and anorexia. The only significant feature found was a thrombocytopenia (91,000/mm³). A presumptive diagnosis of dengue fever was made; treatment with antipyretics, rest and optimum hydration were advised. Test for malaria was negative, dengue NS1 antigen positive and Ig (immunoglobulin) M dengue serology were positive.

After a further 7 days, fever and vague abdominal discomfort ensued. There was no organomegaly on abdominal examination. In view of the persistent fever, other aetiologies were considered, such as typhoid, leptospira, rickettsial diseases, influenza and influenza-like illnesses. A blood culture was found to be positive for salmonella typhi. Treatment with oral Cefexime at 400 mg b.i.d. was commenced and continued for 10 days. The fever resolved completely and the appetite improved significantly.

Case report 2

A 32-year-old woman presented with fever of 1 day’s duration, associated with headache, myalgia, nausea and prostration. Significant findings were a positive tourniquet test and a relatively low platelet count (110,000/mm³). Dengue NS1 antigen was positive, while the test for malaria was negative, and so conservative treatment was advised. Dengue IgM dengue serology was positive after 5 days of fever. Fever persisted after day 8 and tended to rise; Widal testing detected Salmonella typhi agglutinins in a titre of 1:160 and blood culture was positive for salmonella typhi. Treatment with oral Cefexime, 400 mg b.i.d. for 10 days resulted in dramatic improvement.

Discussion

Though the first recognised epidemics of dengue fever were known early in the 1780s, ⁶ concurrent illness with dengue and typhoid has rarely been reported. The incidence of both dengue and typhoid fever peaks during the monsoon season, and early clinical signs of both the diseases are non-specific and similar. It is important to distinguish typhoid fever from dengue as early antibiotic therapy in the former leads to a favourable outcome, while dengue as such has no specific treatment and is treated symptomatically. Only one case report of concurrent illness has been reported. ⁵ A few case reports show an association of bacterial, fungal and viral infection simultaneously with dengue infection. ⁷ Lee et al. also observed concurrent bacteraemia in a patient with dengue fever who had a fever prolonged for more than 5 days and suggested a predominance of microflora in this case. ⁸

A possible interaction between dengue and typhoid may arise through intestinal endothelial damage or intestinal haemorrhage, or through immunosupression superimposed by virtue of the initial virus illness.^8,9

Both patients presented with a sudden onset of high fever, myalgia and gastrointestinal disturbances including nausea, abdominal pain and loss of appetite. Physical examination was unremarkable, except for a positive tourniquet test in the second patient. According to WHO guidelines, the acute febrile phase of dengue usually lasts 2–7 days. ¹⁰ Clinicians should be alert to a progressive leucopenia in the early phase of dengue fever.

In both cases fever persisted in the second week of illness. There was, thus, a possibility of some concurrent infection. Owing to a high prevalence of both dengue and typhoid in India, a high degree of suspicion for the latter must be maintained.